There are several different ways of producing subordinate clauses:
- with that ... that he becomes/should become a baseball player
- with a marked infinitive ... [him] to become a baseball player
- with an unmarked infinitive ... become a baseball player
- with for + a marked infinitive ... for him to become a baseball player
- with a gerund ... becoming a baseball player
Each lexical verb 'licenses' (permits) some of these, but not all. Want, for instance permits:
- He wants to become a baseball player ... with an implicit subject = the subject of the main clause
- I want him to become a baseball player ... AND
- I want for him to become a baseball player ... with a different subject
But you may not say
- ✲I want that he should become a baseball player.
- ✲He wants become a baseball player.
- ✲He wants becoming a baseball player ... and so forth.
And when you move the pieces around to create what grammarians call cleft constructions, like your What sentences, you have to follow the requirements of the verb, as in What he wants ... is to become.
Do is a little tricky, because it's not ordinarily a main verb; but with other verbs it acts like a modal, taking an unmarked infinitive: Yes, the paper shredder does cut the paper into small pieces. That's why, in your example, you may use either to become to agree with wants or unmarked become to agree with do. In the other construction, though, there is no such ambivalence, and you want the unmarked infinitive:
- What the paper shredder does is tear the paper into small pieces.
✲ marks an utterance as unacceptable
Many thanks for your answer!! It was really helpful. One more question, so does it mean that any expression 'I want that ....' is incorrect? – Dude – 2013-02-27T22:39:33.340
@Batman Of course I want that car is perfectly OK; but Yes, it is incorrect when that is being used as a subordinating conjunction. That doesn't mean you'll never find this use, but it is neither formal nor colloquial. Take a look at this NGram.
– StoneyB on hiatus – 2013-02-27T22:45:11.143@StoneyB Yes subordinating conjunction is what I meant :) – Dude – 2013-02-27T22:48:05.903
@Batman I was pretty certain you did, but subsequent learners may not! – StoneyB on hiatus – 2013-02-27T22:49:20.470
@StoneyB I have a few doubts. I have read your answer. And according to that the following sentence should be correct - All they want is to get a house for free and the sentence - All they want is get a house for free - is incorrect. I believe it's not incorrect. Though in COCA what sentence I got is All they want is get a house for free. Another sentence in CGEL - What you must do is (to) apply for special leave - the to is optional. Did I get something wrong from your answer? – Man_From_India – 2015-02-03T06:56:32.100
@StoneyB (cont...) I have really problem to understand when to use to and when to consider it optional in this kind of cleft sentence. Please help. Thanks. – Man_From_India – 2015-02-03T06:57:05.960
@Man_From_India I don't find that sentence on COCA. What's the source? You have to expect slips of the tongue in speech, and typos in written texts. ... With clefts: use whatever form is called for by the verb in the Wh- clause: want...to* get*. I generally use an unmarked infinitive with do, and I advise you to stick to that; but in speech (and colloquial writing) you will find many people using the marked infinitive. – StoneyB on hiatus – 2015-02-03T13:52:37.667
@StoneyB I am sorry. That sentence is a comment from a user. And chances are that he made a mistake there. I was not much careful. Here is the link. http://corpus.byu.edu/glowbe/ Most wired usages are written by users.
– Man_From_India – 2015-02-03T14:13:55.777@StoneyB So these sentences are also correct - 1. What would be better is to call them before hand. 2. All the tree need now is watering. And in #1 the to is not optional. Am I right? – Man_From_India – 2015-02-03T14:16:10.240
@Man_From_India 1. Correct, but the to is not optional: the idiom is "It would be better to call them beforehand", "To call them beforehand would be better." 2. "All the tree needS now is watering" = "The tree needs watering". Watering here is a gerund. – StoneyB on hiatus – 2015-02-03T14:26:58.497