How can I say "can" in the future form?



If someone wants to say me that he can not do something in the next week but just after this next week. What is the way on English to say that?

I will not can do that

or simply

I can not do that next week

Is there no form for the future like many other languages?

Judicious Allure

Posted 2015-10-04T00:43:57.180

Reputation: 24 598

Sorry, but the idea re the future is very simple: I will not be able to do that. – Lambie – 2020-06-07T19:08:52.143



There is no such way of casting any of the modal verbs can/could, may/might, must, shall/should, will/would in future form with will.

This is because the modal verbs are all defective: they have only two forms, past and present (must has only one), so they lack the infinitive form which follows auxiliary will.

There are two ways around this.

  1. The simple present of most verbs can be used with future reference, so one thing you can do is simply use can with some indication of futurity.

    I cannot do that tomorrow.
    I may do that tomorrow.

  2. The other thing you can do is employ the infinitive of a "periphrastic" construction as the complement of will. With can, for instance, the periphrastic construction is BE able to; with will it's BE going to.

    I will not be able to do that.
    I will be going to do that.

    Other periphrastics which come in handy for this are:

    for may/might: be permitted/allowed to: He will be permitted to do that.
    for must: be obliged/required to: He will be obliged to do that.
    for should: be expected to: He will be expected to do that.
    for will: be going to: He will be going to do that.

    There are more, because all the modals have a wide variety of meanings, and many of these meanings have one or more periphrastics.

Note that the modal verbs have no participles either, so they can't be cast in the perfect construction or employed as gerunds or adjectives. Again, the way around this is to employ the appropriate periphrastic:

I have been able to do that.
Being able to do that would be helpful.

Modal verbs are intransitive and can't be cast in the passive, and they're stative and therefore can't be cast in the progressive, so you don't have to worry about those forms.

StoneyB on hiatus

Posted 2015-10-04T00:43:57.180

Reputation: 176 469

Thank you for your answer. The real option is to use in the structure of: "He will not be able to do that in the next week". This is the best way for me to express what . Thank you. – Judicious Allure – 2015-10-04T01:29:27.963

1@Assiduous Note that *in the next week* is not the same thing as next week. "I can do that next week" means during the seven days starting next Sunday or Monday. "I can do that in the next week" means during the seven days starting today. – StoneyB on hiatus – 2015-10-04T01:37:08.050

Also, (although this example is not responsive to "cannot/not able), did you mean "will be going to do that", or " will not be going to do that"? It seems odd that he will be doing it, even though he will not be able! (But otherwise, great explanation!) – Brian Hitchcock – 2015-10-04T12:32:15.380


For me, 'could' is a more logical future tense of 'can', because 'will be able to' is the future tense of 'can' when we talk about ability. So when we talk about possibility, we have to use 'could' to express 'can' in the future.

Sanaa Abdouh

Posted 2015-10-04T00:43:57.180

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