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Structure of Be able toCan Can is an auxiliary verb, a modal auxiliary verb. We use can to:
Structure of Can subject + can + main verb The main verb is always the bare infinitive (infinitive without "to").
Notice that:
Use of Can Can: Possibility and Ability We use can to talk about what is possible, what we are able or free to do:
Normally, we use can for the present. But it is possible to use can when we make present decisions about future ability. A. Can you help me with my homework? (present) B. Sorry. I'm busy today. But I can help you tomorrow. (future) Can: Requests and Orders We often use can in a question to ask somebody to do something. This is not a real question - we do not really want to know if the person is able to do something, we want them to do it! The use of can in this way is informal (mainly between friends and family):
Can: Permission We sometimes use can to ask or give permission for something: A. Can I smoke in this room? B. You can't smoke here, but you can smoke in the garden. (Note that we also use could, may, might for permission. The use of can for permission is informal.) Could Could is an auxiliary verb, a modal auxiliary verb. We use could to:
Structure of Could subject + could + main verb The main verb is always the bare infinitive (infinitive without "to").
Notice that:
Use of Could Could: Past Possibility or Ability We use could to talk about what was possible in the past, what we were able or free to do:
We use could (positive) and couldn't (negative) for general ability in the past. But when we talk about one special occasion in the past, we use be able to (positive) and couldn't (negative). Look at these examples:
Could: Requests We often use could in a question to ask somebody to do something. The use of could in this way is fairly polite (formal):
Be able to Although we look at be able to here, it is not a modal verb. It is simply the verb be plus an adjective (able) followed by the infinitive. We look at be able to here because we sometimes use it instead ofcan and could. We use be able to:
Structure of Be able to The structure of be able to is: subject + be + able + infinitive
Notice that be able to is possible in all tenses, for example:
Notice too that be able to has an infinitive form:
Use of Be able to Be able to is not a modal auxiliary verb. We include it here for convenience, because it is often used like "can" and "could", which are modal auxiliary verbs. Date: 2015-12-17; view: 3820
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