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Explanations and examples Practice exercises Ability : can/ could/ be able to (=saying whether you are able to do something) If you want to say whether someone is able to carry out an action, use can. e.g. Guy can speak Russian. When you put these sentences into the past tense, use could. e.g. He was late for school because he couldn't find his bag. Use could if there are conditions controlling whether the event will take place. e.g. I could leave tomorrow, if I had the money. In general, we use be able to when we talk about a specific achievement (particularly if it is difficult, requiring some effort) rather than a general ability. Here be able to means succeed in doing something or manage to do something. e.g. He has now recovered from his injury and is able to drive again. However, we commonly use can or could , even when are talking about specific occasions, with verbs of the senses, feel, hear, see, smell, taste, and verbs of ¨thinking〃, believe, decide, remember, understand. e.g. I canˇt decide where to go for my holiday. We donˇt use be able to 冘 when we talk about something that is happening as we are speaking: 冘 before be + past participle: e.g. This furniture can be assembled by anyone, with just a screwdriver. We use be able to, not can or could, if the idea we want to express needs a to-infinitive, an-ing form, of a perfect tense, or if it follows another modal verb: e.g. We were very lucky to be able to live in the country during our childhood. We use will be able to, not can, to say that something will be possible in the future:
e.g. f the snow carries on like this, very few people will able to get to the concert. have been able to do something to mean that someone has succeeded in doing something. could have done something to mean that someone was able to do something but did not do it. canˇt/ cannot to be unable to do something, because you do not have the ability, time equipment, etc; not be able to to be used mostly in past or future tenses. In the present tense, use canˇt/ cannot. 1. Two eyes . see more than one. / The theatre . seat 2, 000 people. 2. Will you . come tonight? / . you come tonight? 3. Iˇm sorry I.( answer) your letter yet. 4. Before liberation few workers. support their families. 5. My students have taught me much, usually by asking questions that I . (not answer). 6. Jenny . leave the hospital only 6 hours after he baby was born. 7. The fire spread through the hotel very quickly but everyone . get out. 8. I . understand the speaker at all because what he said was beyond my understanding. 9. It was awful, not ..see you for so long. 10. Since he left, none of the team members . match his enthusiasm. 11. We may . move some of the staff to a different department. 12. Antia . speak three languages before she was six. 13. When the new road is built, I . drive to work in under half an hour.
Keys: 1. can; can 2. be able to; can 3. havenˇt been able to 4. could 5. couldnˇt answer 6. was able to 7. was able to 8. could not 9. being able to 10. have been able to 11. be able to 12. could 13. will be able to Permission: may/ might/ can/ could (=allowing someone to do something) If you want to give or ask for permission, use can or may. May is more polite or formal than can. e.g. You can leave when the bell rings. Customers may purchase extra copies at half price. Could is a polite way of asking for permission. e.g. Could I leave early today? Might is a very formal and old-fashioned way of asking for permission only. e.g. Might I borrow your umbrella? If we want to put extra pressure on someone to give a positive answer we can use can't or couldn't. For example, you might use couldn't where you expect that the answer is likely to be 'no', or where permission has been refused before: e.g. Can't/Couldn't we stay just a little bit longer? Please? To give and refuse permission we use can and can't: e.g. No, you can't have another chocolate. Notice that we prefer can/can't rather than could/couldn't to give or refuse permission. We use can (for the present or the future) and could (for the past) to report permission. e.g. Jim says that we can borrow his house as long as we leave it clean and tidy. To report that in the past someone had general permission to do something, that is, to do it at any time, we can use either could or was/were allowed to. However, to report permission for one particular past action, we use was/were allowed to, but not could: e.g. Last century, women were not allowed to/ couldnˇt vote. e.g. Although he didn't have a ticket, Ken was allowed to come in. In negative sentences, we can use either couldn't or wasn't/weren't allowed to to report that permission was not given in general or particular situations: e.g. We couldn't / weren't allowed to open the presents until Christmas. If we use the present perfect, past perfect or an infinitive, we use be allowed to, not can/ could. e.g. They have been allowed to keep the Roman coins they found in their garden. 1. He said we . use the car, too. 2. She is unlikely to .travel on that airline again. 3. .I come in? 4. This kind of thing.(not ) happen. 5. .I trouble you with a question? 6. ---.I smoke here? --- No, you./ Please donˇt./ Yes, please. 7. You . take this seat if you like. 8. ----. I ask for a photo of yours? --- What did he say? ----He asked if he. look at my photos? 9. --- So you mean I have been too strict with you? --- Well, if you
