Conditional: "are not" vs. "don't be"



Consider the following phrases (someone is talking with a friend who is challenging some mobsters):

  1. If you are not careful, they will catch you.


  1. If you don't be careful, they will catch you.

Is the second option acceptable or usual? Are they both in according with grammar rules?


Posted 2014-12-27T15:27:41.823

Reputation: 697

3Yes, both versions are fine and standard English. In your 1st version, the verb "are" is an auxiliary BE (e.g. "If you aren't careful …"). In your 2nd version, the verb "be" is a lexical verb--but there are constraints on where the lexical BE can be used. (CGEL page 114, "Lexical be") – F.E. – 2014-12-28T00:02:57.923

@F.E. Glad you left that comment. A question for you now that you've all gone an opened that can of worms in my head. Is BE lexical in "If you're careful"? Do you reckon ... ? (cuz I'm cnfoozed) :) – Araucaria - Not here any more. – 2014-12-29T02:46:59.087

@Araucaria Lexical BE has only one shape: "be". It is used as a plain form; and for some speakers, it can also be used for present tense except for 3rd singular. So, that means that "If you're careful …" is auxiliary BE. – F.E. – 2014-12-29T03:07:17.993

@F.E. If that be the case, how do we know that 2. there isn't a subjunctive BE, or that 2. isn't an alternative negative form of 1 - because DO necessitates a plain form anyhow? (did you see what I did there with that protasis?) – Araucaria - Not here any more. – 2014-12-29T03:13:48.383

@F.E. Am just being troublesome ( - ish), because I have no-one to talk to right now :D Am going to hit the hay. Am working in 5 hours .. :) – Araucaria - Not here any more. – 2014-12-29T03:15:46.510

@F.E. Cross posting ... but did you see what I did with that protasis, before I delete my last couple of comments? EDIT but might do a question in my lunchbreak tomorrow ... – Araucaria - Not here any more. – 2014-12-29T03:17:09.147

1@F.E. Will see if I get the chance tomorrow- but I'm done for today. Happy NFLing! – Araucaria - Not here any more. – 2014-12-29T03:23:40.857

1@Araucaria Errrrrr-rrr! I'm thinking of maybe actually writing an answer post on this topic of lexical "BE" usage (and an associated nonstandard dialect), just to put down a straightened out layout of what I think is all involved, as I've got a good bunch of comments in my margins of CGEL. – F.E. – 2014-12-30T07:42:30.133

1@F.E. Yes, do!! I look forward to reading it :) – Araucaria - Not here any more. – 2014-12-30T08:17:16.930



Consider the following phrases (someone is talking with a friend who is challenging some mobsters):

  1. If you are not careful, they will catch you.

  2. If you don't be careful, they will catch you.

Is the second option acceptable or usual? Are they both in according with grammar rules?

SHORT VERSION: As to whether or not both versions are acceptable, the answer is:

  • Yes, both versions are grammatical and are considered to be standard English.

In your 1st version, the verb "are" is an auxiliary BE being used in a typical copular usage (usage similar to "If you aren't careful …"). In your 2nd version, the verb "be" is behaving as a lexical be--but there are constraints on where the lexical be usage can be used.

This explanation is based on my interpretation of the info that is in the 2002 CGEL.


Your version #1 ("are not") might be considered to be slightly more formal of a style than a version that uses "aren't":

  • 1.a If you are not careful, they will catch you. -- (original #1)

  • 1.b If you aren't careful, they will catch you.

Both #1a and #1b are using the auxiliary verb "BE" where the verb "BE" is being used as a copular verb. And both versions are fine.

As to your version #2 ("don't be"), the verb "BE" is behaving as a lexical verb, taking do-support in a present-tense negative construction:

    1. If you don't be careful, they will catch you. -- (original #2)

Some background info: CGEL considers there to be six main uses of the verb lexeme BE. In CGEL page 113:

2.5.7 Be

We distinguish the following uses of be:


  • i. She was a lawyer. -- [ copula be]
  • ii. She was sleeping peacefully. -- [ progressive be]
  • iii They were seen by the security guard. -- [ passive be]
  • iv. You are not to tell anyone. -- [ quasi-modal be]
  • v. She has been to Paris twice already. -- [ motional be]
  • vi. Why don't you be more tolerant? -- [ lexical be]

Your version #2 is similar to [ ], which involves a lexical be usage.

In CGEL page 114 has info related to lexical be usage, including examples:

Lexical be

This is found with why + do and with if:


  • i.a. Why don't you be more tolerant?

  • i.b. Why doesn't he be more tolerant?

  • ii.a. If you don't be quick you'll lose.

  • ii.b. If he doesn't be quick he'll lose.

  • iii.a. % If you be quick you'll win. -- (grammatical in some dialects only)

  • iii.b. * If he be / bes quick he'll win. -- (ungrammatical)

Their discussion of [63] is:

The why construction [i ] is virtually restricted to the negative: ? Why do you be so intolerant? is at best very marginal. Pragmatically [i ] conveys "You/He should be more tolerant" and thus bears some resemblance to the imperative, but syntactically it is quite distinct from the imperative construction by virtue of having a present tense form, not a plain form. This is evident from the person-number contrast between don't in [i.a] and doesn't in [i.b], for imperatives with a 3rd person singular subject do not differ in verb-form from those with a 2nd person subject (cf. Somebody open the door, please).

The same person-number contrast is seen in the conditional construction [ii / iii ], which again conveys that you/he should be quick (in order to win / avoid losing). This time, however, some speakers allow be in the positive, but with no corresponding 3rd person singular form.

With additional info:

Two points about be follow from the data of [63]. The first is that in these constructions it behaves as a lexical verb, taking do-support in present tense negatives. The second is that for speakers who use construction [iii.a] the lexical and auxiliary uses correspond to different lexemes, for the inflectional forms are different. Lexical be has only the one realisational form be, but it realizes either the plain form (when taking do-support) or (in positive conditionals) a present tense form, distinct from the are that we have with auxiliary be.

What the above CGEL info means is that, with respect to the lexical be usage, there are two dialects of standard English: Dialect A, Dialect B.

DIALECT A: The speakers of this dialect consider only the unmarked examples in [63], which are the four examples in [63.i-ii ], to be grammatical:

  • i.a. Why don't you be more tolerant?

  • i.b. Why doesn't he be more tolerant?

  • ii.a. If you don't be quick you'll lose.

  • ii.b. If he doesn't be quick he'll lose.

The examples are all negatives and used under the constraint of being in constructions involving "why + do" or" if". The examples are using the auxiliary verb lexeme "BE".

These speakers do not accept [iii.a], which is ungrammatical to them: * If you be quick you'll win.

DIALECT B: The speakers of this dialect accept the four examples in [63.i-ii ] that the Dialect A speakers accept, and also accept example [iii.a ] as grammatical, which is now unmarked:

  • iii.a. If you be quick you'll win.

The reason why this example is not acceptable for Dialect A speakers is because it is not a negative.

Dialect B speakers consider all the lexical be usages to be using a different verb lexeme, which is a lexical "BE" verb lexeme, and it is different from the auxiliary "BE" lexeme. That is, they have two different verb lexemes, while Dialect A speakers have only the one standard auxiliary "BE" lexeme.

The reason why Dialect B speakers consider that the lexical be usage to be using a different verb lexeme -- the lexical "BE" verb lexeme -- is because it has its own present tense verb form: "be". For instance, the lexical "BE" lexeme's 2nd person form is "be", while the auxiliary "BE" lexeme's 2nd person is "are".

This lexical "BE" lexeme is rather defective in that it only has a plain form and present tense form, and even the present tense form is defective in that it has no 3rd person singular form.

NON-STANDARD DIALECT: As to example [63.iii.b], it is ungrammatical for standard English. This is why it is marked with "*":

  • iii.b * If he be / bes quick you'll win.

Notice that the example ("he be/bes") uses 3rd person singular, which is not acceptable for either Dialect A or Dialect B speakers.

ASIDE: Note that for many speakers, there is a non-standard alternate for [63.ii.b] in informal or colloquial style:

  • 63.ii.b. If he doesn't be quick he'll lose. -- (standard, CGEL)

  • alternate: ! If he don't be quick he'll lose. -- (non-standard)

And also, as to [63.iii.b], there is a non-standard alternate for some speakers:

  • 63.iii.b. * If he be / bes quick he'll win. -- (ungrammatical, CGEL)

  • alternate: ! If he be quick he'll win. -- (non-standard)

Note that CGEL is the 2002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language.


Posted 2014-12-27T15:27:41.823

Reputation: 5 118

2+1 nice post. One question for now. What kind of BE is this?: "Be an idiot like that again and I'll fire you". – Araucaria - Not here any more. – 2014-12-31T10:03:53.187

Oh just in case I can tempt you, or fancy adding a comment. look here!

– Araucaria - Not here any more. – 2014-12-31T15:52:50.580

@Araucaria I think that according to CGEL, a standard auxiliary verb BE, its plain form heading an imperative clause in a construction having a semantic meaning of a conditional. Oh, interestingly, this brings up a longer topic: Could some unusual, or not-fully-standard, "subjunctive" uses of BE actually be Dialect B's use of the lexical BE lexeme? -- But didn't want to try looking into that one, not this year. :) – F.E. – 2014-12-31T19:33:49.250

2@Araucaria Yeah, I glanced at that thread. EL&U is not a place for serious grammar discussion, or for accurate grammar opinions. – F.E. – 2014-12-31T20:18:47.127


Your comment above aside, any chance with a reopen, upvote helping-hand here? As you'll see, it's a basic job that needs doing by someone ...

– Araucaria - Not here any more. – 2015-01-02T18:46:28.167

1@Araucaria Done! :D -- But I don't know why you're trying to teach them grammar, like, ya can lead a horse to water but ya cannot make it drink, ya know that one, right? Like, ya know, that place over there has gotten worse during and since the last moderator elections. Them high-rep-SWR-users don't like their grammar ignorance exposed like you're doing, them gonna hate you bad! :D Now I go and amuse me-self by browsing that thread--Reading them folks opinions, that make me feel sooooo smart and knowledgable on grammar! – F.E. – 2015-01-02T19:50:31.133

@Araucaria Hey, that last EL&U question of yours is an easy one! (I remember one other of yours, where the responders didn't even realize they were being puzzled by a direct object.)

– F.E. – 2015-01-02T19:55:23.783

@Araucaria Oh, I just read this "chat" session. What's that term for not being able to know what one doesn't know? A college textbook 101 English grammar would be useful to, er, many. I was going to say 101 English syntax, but I am finding that many linguists, especially famous ones, more so those that are famous generative linguists, still conflate traditional grammar, such as P.O.S., with today's English grammar.

– F.E. – 2015-01-02T20:19:34.947

@Araucaria And I'll try to not make any comments over there, such as "Obviously each one of those are nouns or noun phrases!" :D – F.E. – 2015-01-02T20:21:20.777

1Oh, come on! One for the road. Just a straight-forward answer ;) Otherwise I'm going to have to get the beeferfan involved and that will be the death of me! :D OK seriously, here's why: there are folks who are going to come onto the site and don't have anywhere else to go.What are they going to read? What kind of help is going to be given to them. What are they going to believe? (Just eat this mushroom, it'll be ok ...) If ELU really gets that bad so that no grammar questions are allowed, what will happen after they pull the plug with ELY to ELL? – Araucaria - Not here any more. – 2015-01-02T21:19:34.327

@Araucaria What Wikipedia article? What question? – F.E. – 2015-01-02T23:16:58.910

The one, erm, here, where one might just have commented :D

– Araucaria - Not here any more. – 2015-01-02T23:19:03.400


@Araucaria I merely glanced over that wikipeida page on noun adjuncts. Er, why would you want to even touch that nonsense. Lordy. Just let it lie and let it die, yup. :D

– F.E. – 2015-01-02T23:29:37.587


@Araucaria This here thread Passive voice of intransitive verbs is gonna be promising a whole bunch of merriment for all! :D -- Ah upvoted that question, too!

– F.E. – 2015-01-03T05:59:41.657


@Araucaria Check this out, Ian McEwan's usage of “must” as a simple past! Ah knew modals were defective lexemes, but, er, a modal auxiliary not having any primary forms? Wow. Lordy. Do you think any dissenting opinions will be made?

– F.E. – 2015-01-03T07:09:04.053

1Hope the NFL was a good showdown! Thanks for the edit, reopen, etc, etc ;) I'm afraid Tchrist started having a go at me (again) the other day and I refused to take it, so now he's close voting all my questions and down-voting all my posts - getting them onto the close-vote circular - :-) I guess he was real embarrassed about me explaining the difference between a phonetic and phonemic transcription. He doesn't know the difference between those either ... – Araucaria - Not here any more. – 2015-01-04T20:17:32.583

1@Araucaria Well that guy is the same guy that tried to pass the 1985 Quirk et al. off as the 2002 CGEL. I doubt he has hardcopies of those two reference grammars, since one has a green cover while the other a red one, and their layout and fonts are quite different. And so, it makes one wonder . . . -- Hey, you're lucky that the moderators haven't deleted your dissenting opinions! :D – F.E. – 2015-01-04T20:30:12.697


@Araucaria Lookie, lookie! I'm contributing over at EL&U! b but it does seem to be a waste of time. :D

– F.E. – 2015-01-04T20:33:06.860


Yes, I know, that's true. But I can't let it go just yet. I kind of enjoy the theatre of embarrassment. Also, I'm waiting for Tchrist to do something as his normal aggressive self but get noticed while he's doing it so that he gets kicked off ELU. Also, the "top" answer to this question has got to be stopped as a reason for closing questions before I quit the site ... if it kills me :) [maybe it will!]

– Araucaria - Not here any more. – 2015-01-04T21:27:49.343

Did you set that link up for me? – Araucaria - Not here any more. – 2015-01-04T22:02:34.967

1@Araucaria Er, that "top" answer only has two downvotes, and one of them is mine. That "top" answer post is pure nonsense, yet it is so typical for EL&U--that's why that site is beyond hope. Yes, that subjunctive thread was kinda for you. It has the usual bad info that is to be expected over there. You've been a member for 7 months now, eh? Ya remember a conversation we had some months ago, about 6 months being a usual length of time before one gets all fed up? :) I'm watching NFL playoffs and doing some grammar reading during the commercial breaks. – F.E. – 2015-01-04T23:53:26.503

1Erm, the other might be from me ... I think it was 4 months you said ... but I was only on three months in and I was already depressed. I'm reading George Orwell and having a traditional Irish stout. I wish I knew something about the NFL playoffs so I could make somekinda witty remark thing, but I don't! Hope it goes well, if you're rooting for someone special in particular! – Araucaria - Not here any more. – 2015-01-05T00:03:02.483

@Araucaria When you have time, will you glance at this deleted post of mine, to see if the "for" could/should be interpreted as a preposition? My brain is mostly wiped out from reading some generative grammar stuff.

– F.E. – 2015-01-07T16:19:20.300

Not if you're H&P! :) Although, it has been argued that the case has not been fully made about for not being a preposition/sub conj in this case (i.e. it's been argued - can't remember where - that not enough has been said to clearly demonstrate why certain subordinators have been retained/included in the class. Indeed my first PhD proposal was about exactly that issue - and the status of infinitival to. – Araucaria - Not here any more. – 2015-01-07T16:24:12.670

1There are two other preposition for s, but that one ain't one of them. Btw, aside, have you ever noticed that this use of to is very prepositiony? – Araucaria - Not here any more. – 2015-01-07T16:29:02.110

1@Araucaria I think there are sometimes where there can be a pair of "PP + to-infinitival", and perhaps/maybe? that PP can be headed by a "for" preposition. I wanted to make sure that the OP's 3 examples weren't like that. Though, in the OP's examples (e.g. #3), that "for" expression sure does seem to have a lot of extra meaning (like a preposition "for"?) when interpreted as part of that example. – F.E. – 2015-01-07T16:29:23.053

1@Araucaria In the OP's #3 example, both the "for" and the "to" seem to have a lot of the prepositions' meanings. I'm not sure if that is partly due to the passive form, and/or the specific matrix clause. – F.E. – 2015-01-07T16:30:51.890

Agreed, a bit like to when it seems to be used with a similar meaning as in order to ... Will double-check the third example, but I don't have H&P with me today! I see we're cross posting:) – Araucaria - Not here any more. – 2015-01-07T16:31:15.583

@Araucaria Would it be better if I undeleted that post and we put our comments in over there? Or just do the comments as we are doing? – F.E. – 2015-01-07T16:32:17.333

I don't think you need worry about this for being prepositional. I'd undelete your post for sure, if I was you:) Perhaps copy some obs over there and delete the others? But try out comments here in the first instance where the people is civilised. – Araucaria - Not here any more. – 2015-01-07T16:40:28.737

@Araucaria Okay, maybe, er … My main concern about "for" being a preposition is the parse: "FOR [ NP + to-infinitive]", for #3. That's not possible, or not possible here in #3, is it? I don't want to stumble into a well-known sort of syntactical issue--and get egg all over my face! :) – F.E. – 2015-01-07T16:46:18.887

I'm pretty confident, but on the other hand if you're feeling unsure, I ever so slightly less confident. Let me check it out when I get home - am still at college at the mo – Araucaria - Not here any more. – 2015-01-07T16:47:42.037

@Araucaria I'm watching your "Bob made a book collector happy the other day" thread, and I'm sorta thinking of opening an ELL thread related to: P.O.S. and syntactic functions and semantic roles -- and maybe use your example sentence as my example! What ya think? – F.E. – 2015-01-07T16:48:53.913

I think that would be something like I did it for James to be happy, or I bought it for Bob to clean the house with, no? – Araucaria - Not here any more. – 2015-01-07T16:49:20.040

@Araucaria But can those two examples of yours have that "For X" be preposed (as done in #3)? And in your 2 examples, they would still be "For"-to-infinitivals, yes? – F.E. – 2015-01-07T16:52:51.410

@Araucaria w.r.t. new ELL question thread: I was thinking of addressing all 3 issues, because the labels of those three topics get conflated together, and a rather simple example might make somethings clearer. E.g. "Bob" is a noun phrase (category) that realizes subject function (syntactic function) that plays the role of agent (semantic role) in the relation made(bob, collector, happy). – F.E. – 2015-01-07T16:56:57.290

1@Araucaria Identifying the actual role label isn't so important here; what's important is separating the semantic role label, whatever it is, from the other labels used for category and function. For instance, many conflate "subject" with the role of "agent", and end up calling an oblique NP as the "true subject" of a passive, e.g. "The ball was thrown by [the mailman]" with "the mailman" as the so-called 'true subject' though it is the agent. – F.E. – 2015-01-07T17:14:33.277

1Ok, sounds good to me! Rushing off to get a bus. Ciao – Araucaria - Not here any more. – 2015-01-07T17:33:00.927

Have you got the details of that post where someone mentioned above might have been blathering rubbish about CGEL and CaGEL - I need to stick that stuff under his comment: *Nobody but nobody has ever once claimed that a multiword phrase is an adverb. It is sad to see people made to waste their time tilting at strawmills* Btw, don't reckon I'm going to get round to reading H&P tonight, not with that question (bit taxing at this hour ...). But will do tomorrow, promise. – Araucaria - Not here any more. – 2015-01-08T02:28:08.210

Oh and do you have any thought about this answer I did. I got a down-vote from said person (getting a couple a day, minimum - ha!). But wondering if I stuffed something up because of the second vote ...

– Araucaria - Not here any more. – 2015-01-08T02:39:17.100

@Araucaria I had given you an up vote on that one! :) -- EL&U is cliquish, and some older members most likely have extra accounts. Anyhow, when I saw your first down vote, I had assumed that it was because you resurrected an old thread. And now, seeing your 2nd down vote, that might be from your "friend" or from one of his minions. Hey, that's EL&U, if you aren't pissing them off, then you're not doing something right (w.r.t. grammar). – F.E. – 2015-01-08T03:45:16.567


@Araucaria Here it is, that phony 2002 CGEL excerpt. Remember to look at an older version of the guy's answer.

– F.E. – 2015-01-08T04:03:57.660

1Oh shucks, can't go to bed just yet then :D Got some comedy reading to do! – Araucaria - Not here any more. – 2015-01-08T04:04:43.977

@Araucaria Here the guy makes an answer post, where the OP had already basically described the answer in her question--and she was probably asking for more of an explanation.

– F.E. – 2015-01-08T04:15:19.250

@Araucaria Apparently Messrs. Huddleston and Pullam have decided to reclassify subordinating conjunctions as prepositions when their argument is a non-finite verb clause but leave them as conjunctions when followed by a finite clause. Makes no sense to me, but this would hardly be the first time I’ve caught Pullam barking up the wrong tree. <== That is one of his many most hilarious stuff that he does! And he ain't even aware of it when he continuously do it! :D

– F.E. – 2015-01-08T04:24:21.373

1EDIT: response to previous: Yes, I think so. Unfortunately, that's the kind of brusque, unfriendly, curt, verging on poisonous, arse-paralysingly tedious attitude that I expect in this case - sadly. – Araucaria - Not here any more. – 2015-01-08T04:24:37.403

1I've already wet myself twice and spewed wine all over the table laughing that :D And I'm keeping lots of that in a file for posterity - or in his case posteriority. Oh geez I definitely need to go to bed ... - Hey, let me off for the lame humour, it's 4.30 am over here. Ciao, but feel free to leave any comments/gems on here to cheer me up on the long slog into work tomorrow! :) – Araucaria - Not here any more. – 2015-01-08T04:31:36.687


@Araucaria Oh, I just notice this: people will always bitch -- which he wrote in his edit history. He sure is a sorry excuse! :D

– F.E. – 2015-01-08T04:59:22.143

1Re your preposition concerns in your other post, I can't find the relevant part in CaGEL. Doesn't help that there's so many for s kicking about! You don't know the relevant section(s) do you? – Araucaria - Not here any more. – 2015-01-10T20:52:44.007

1@Araucaria I think that somewhere in there they give an example of a "PP + to-infinitival" where the 'for-PP' isn't the subject of the to-infinitival (but I'm not sure if they did), but I couldn't quickly find it the other day when I was looking for it. (Maybe in the adjunct chapter?) But I'm too busy with this generative grammar stuff at the moment. :) – F.E. – 2015-01-11T01:53:34.623


I googled a bit and it seems that this sentence is considered more "formal":

If you are not careful, they will catch you.

The second sentence is grammatical, but is considered somehow less "formal" and is used more often in speech, less often in "formal" writing:

If you don't be careful, they will catch you.

Are and be are forms of the verb to be, which has eight forms in all: be, being, been, am, is, are, were, was. This is the most diverse verb in the English language. "Be" is its basic form.

Why "don't be careful" is not so "formal", despite being used in speech often?

One discussion, at OneStopEnglish, mentions this use. It says that in imperative sentences - when we command someone to do or not to do something - we use the verbs do and don't to support the verb be:

Do be seated; Don’t be stupid.

But in the indicative sentences - when we do not command someone but merely describe something - we don't use do to help be:

I don't be stupid. (! this sentence is wrong)
I am not stupid. (this sentence is okay: the same verb "to do", but now, without the support of the auxiliary verb "don't", it can assume the form am that agrees with the first-person pronoun I.)

But this use of don't to help be (as in "don't be stupid") overflows into if-clauses in spoken language:

If you don’t be quiet, I’ll send you to your room! ("non-standard" sentence used in spoken language)
If you aren't quiet, I'll send you to your room! ("standard" sentence)

Could this "spoken-language" construction be used in all cases? I guess not. Imagine a customer saying to a car dealer:

If this car doesn't be blue, I will not pay you. (sounds weird to me)
If this car is not blue, I will not pay you. (sounds better)

Reference: CGEL, page 113, "the six uses of be" (a short excerpt at the Language Log)


Posted 2014-12-27T15:27:41.823

Reputation: 36 949

2+1, but I'm not sure it's exactly true that "don't be" in non-imperatives is extended from its use in imperatives. Rather, I think that it's some varieties of English restrict "lexical" uses of be (the sense of be found in "don't be silly" or "he's being silly") to the imperative/infinitive/subjective be and the gerund/participle being, whereas others allow it to be used as a more-or-less regular verb. Varieties of the latter type will accept "If you don't be careful", or (from a movie preview I once saw) "What do we do?" "We be ourselves." – ruakh – 2014-12-28T00:19:08.873

2+1 I think the key difference between If this car don't be blue and If you don't be careful is that these are really two different BEs. BE blue is the ordinary copular use of BE, attributing a quality to the subject. BE careful is the 'behavioral' use of BE, the one we find with BE in the progressive, meaning BEHAVE. "John's a jerk" is copular: it means that's the kind of guy John is. "John is being a jerk* is behavioral: it means that's how John is behaving right now. The imperative is, I think, always behavioral. – StoneyB on hiatus – 2014-12-28T01:12:32.397

2There is lack of numerical agreement in car don't. You should write If this car doesn't be blue, for a fair comparison with If this car is not blue. – Dawood ibn Kareem – 2014-12-28T01:42:29.230

1@StoneyB you got the point, they sound a little different to me because of these two "meanings" of BE. In some languages we can have two variations of BE. The BE like a permanent state or the BE like a moment state. The "are not" sounds like the first one, like a behavior that the guy must have like a part of his own, the "don't be" is like a thing that he may achieve. – Apprentice – 2014-12-28T03:14:50.270

1Thanks, @DavidWallace! Fixed. Thanks, StoneyB, Ruakh, Apprentive, for the interesting comments! – CowperKettle – 2014-12-28T06:58:07.420

1@CopperKettle Just responding to your comment/question in my (now deleted) post here. I think you can probably still see it! BE is called a copula verb mainly because it has no real meaning and takes a complement which is a PC describing the subject. However, it is classified as an auxiliary not because of any complements that it takes or doesn't take in different situations but because of the special NICE properties that it shows. (i.e. its role in negation, inversion, emphasis and code). While copula is an important term describing this verb, auxiliary describes ... – Araucaria - Not here any more. – 2014-12-29T02:09:34.190

1@CopperKettle ... a subcategory of the word category verb in the same kind of way that pronoun may indicate a subcategory of the class noun [ depending on your grammar ]. You might be wondering why I deleted my post, the reason has to do with subjunctives, imperatives and some weird stuff that happens in conditionals. This plus the fact that the analysis everywhere on this seems to be a bit thin - including CaGEL! And I'm no longer sure what I think - or can usefully say ... :) – Araucaria - Not here any more. – 2014-12-29T02:17:43.347


@CopperKettle ... If you're interested in NICE properties and auxiliaries, I did a wee post here and another here. They aren't all that good but I don't know of any others on SE ...

– Araucaria - Not here any more. – 2014-12-29T02:19:55.883

@Araucaria - thank you for being so NICE! (0: Thanks for the links! I'll surely read up on this! – CowperKettle – 2014-12-29T05:02:10.353