_牛津上海版八年级上册be able to与ought to讲解及练习（有答案）

1、语法：be able to &ought to1. be able to的用法be able to具有现在过去和将来等多种时态。时态肯定否定疑问与回答现在am/is/are able toam/is/are not able toAre you/Is he able to.?Yes, I am. / he is.No, Im not. / he isnt.过去was/were able towas/were not able toWere you/Was he able to.?Yes, I / he was.No, I / he wasnt.将来will be able towill

2、 not be able toWill you / he be able to.?Yes, I / he will.No, I / he wont.解析：be able to / can相同点：当表示“能力”时，差别不大，其后均跟动词原形。一般情况下，两者可互相替换。不同点：1) can只有一般现在时(can)和一般过去时(could)两种形式；而be able to有更多的时态形式，如：一般现在时(be able to), 一般过去时(was/were able to), 一般将来时(will be able to) 和现在完成时(has/have been able to)等。2) be

3、able to 相当于manage to do sth.表示经过一番努力，终于能完成某事；而can无此用法。用于否定的陈述句时两者都有此用法。3) can能用来表示“请求，许可”，be able to无此用法。4) can有被动语态，主语为人或物皆可，而be able to只接不定式的主动形式，不接表示被动的不定式，也不可用无生命的名词作主语。The work is able to be done by him. （误）He is able to do the work. （正）2. ought to 的用法1）表示义务，责任等应当，应该We ought to obey school rule

4、s. 我们应该遵守学校的规则。2） 表示劝告，建议等应当，应该You dont look well. You ought to go to see a doctor.你看起来脸色不好，你应该去看医生。3） 表示猜测，期望应该It ought to be a fine day tomorrow.明天应该是晴天。4）注意：ought to的疑问式是将ought提到句首构成，否定式是ought not/ oughtnt to, 其反意疑问句有两种形式。一般疑问句：Ought we to do it at once? 我们要立刻做吗？肯定回答：Yes, we ought to.是的，我们要。否定回答：

5、No, we oughtnt to. 不，我们不要。反意疑问句：He ought to be here now, shouldnt / oughtnt he?他现在应该在这，难道不是吗？PracticeI.Choose the best answer. （选择最恰当的答案）1. I think a student _ to broaden his mind.A. oughtB.shouldC.mustD.may2. You _ to go to school today because it is Saturday today.A. needntB.neednt toC.dont need t

6、oD.dont need3. _ you _ make a homepage on the Internet soon?A. Can, be able toB.Do, able toC.Were, able toD.Will, be able to4. -Must I return the magazine to you right now, Tom? -No, you _. You may keep it until next week.A. mustntB.cantC.shouldntD.neednt5. The Internet _ us _ get more information.A

7、. enable toB.enables, forC.enables, toD.able, to【答案】1.A 2.D 3.D 4.D 5.C II. 选用may, must, can, cant, should填空：1. “_ your brother speak English very well, too?” No, he _.”2. “_ you play tennis?” “Yes, I _.”3. The box is very heavy. Tom _ move it.4. “What about seeing a new film this evening?”  “I

8、m afraid I _. I _ finish my English exercises this evening.”5. This fish wont keep fresh, we _ eat it now.6. You _ start now, or youll be late.7. Excuse me, sir. _ I ask you a question, please?8. Im not sure about the news. It _ or _ not be true.9. Lily isnt here. She _ have gone to the school libra

9、ry, or she _ have gone to the meeting room, or she _ have gone home. Who knows?【答案】1.Can, cant 2.Can, can 3.cant 4.cant, must 5.must 6.must7.Can 8.may, may 9.may, may, mayHomeworkI.Choose the best answer. （选择最恰当的答案)1. We all agree _ him.A. toB.atC.withD.for2. Toms father is worried _ his health.A. a

10、boutB.atC.withD.for3. She gets angry easily. So she has made _ friends here.A. a littleB.littleC.fewD.a few4. The headmaster often tells us _ dishonest.A. beB.to beC.not beD.not to be5. You dont look _. Whats wrong with you?A. wellB.goodC.niceD. happily6. Please help _ to make a cake, will you?A. IB

11、.meC.youD.yourself【答案】1.C 2.A 3.C 4.D 5.A 6.DII.Complete the following passages with the words or phrases in the box. Each word can only be used once. （将下列单词或词组填入空格，每空限填一词，每词只能填一次）A.OtherB.easyC.usefulD.becauseE.DifferentWhy do many people want to learn English? It is _1_ to answer this question. Ma

12、ny boys and girls learn English at school _2_ it is one of their subjects required for study. They study their own language, maths, English and other subjects. Some people learn it because it is _3_ for their work. Many people learn English for their higher studies, because in college or university

13、lots of their books are written in English. _4_ people learn English because they want to read newspapers and magazines in English.A.channelsB.viewC.for a long timeD.gamesE.outsideWith so many fun cartoons and computer games, its hard to let students go to play outdoors. It is easy to get fat if you

14、 watch TV _5_. An American website called Nickelodeon shuts down its cartoon _6_ from noon to 3 p.m. on a special day every year. They want the kids to go out and play with family. They call this activity “Worldwide Day of Play”. When you play _7_, you can breathe the fresh air and see nice _8_. You

15、 can also make many friends. Outdoor fun can happen any time. Do you play outdoors today?【答案】1.B 2.D 3.C 4.A 5.C 6.A 7.D 8.BIII.Complete the sentences with the given words in their proper forms. （用所给单词的适当形式填空）1. There are many _ in the old house. (mouse)2. This my _ time to visit Beijing. (one)3. Th

16、e little boys can clean the house by _. (they)4. She will be a teacher after _ from university. (graduate)5. Mary enjoys _ with her friends on the computer. (chat)6. As a new driver, you should drive your car _. (slow)7. He looked _ because he lost his bike. (worry)【答案】1.mice 2.first 3.themselves 4.

17、graduation 5.chatting 6.slowly 7.worriedIV.Rewrite the following sentences as required. （按要求改写句子）1. He has lunch at home. （改为否定句）He _ _ lunch at home. 2. There is little milk in the bottle. （改为反意疑问句）There is little milk in the bottle, _ _?3.We can use the mouse to control the computer. （对划线部分提问）_ can you do _ the mouse?4. We should search for information before we write the report. （保持句意基本不变）We _ _ search for information before we write the report.5. It took the girl an hour to make the model plane. （保持句意基本不变）The