九年级英语二单元语法.doc

Unit2 It must belong to Carla 重点语法表示推测的情态动词。 在英语中，表示对某件事物的确定程度，即表示推测的时候，我们通常会用到以下情态动词，must, might, could, may, cant, couldnt. 一. can和could的区别和用法1can表示体力和脑力方面的能力，或根据客观条件能做某种动作的”能力”。 例如：Can you speak English？ What can I do for you？Can you make a cake？ can用在否定句和疑问句中时有时表示说话人的 “猜测”或 “不肯定”例如：Where can he be？ Can the news be true？（在日常会话中，can可代替may表示”允许”，may比较正式） 2. could 是 can的过去式，表示过去有过的能力和可能性，还有怀疑和不肯定的意思（在否定和疑问句中）。 例如：The doctor said he could help him（能力）She couldnt skate when she was five years old. （能力）At that time we thought the story could be true（可能性） could用来提问，是有礼貌的请求 Could. Please? 语气较为婉转。 例如：Could I speak to Mr. Smith, please? Could you help us carry this box, please? 二. 跟上组词一样, might也是may的过去式,其用法如下:1. may的用法: a. 表示”允许”或”请求”。 例如：May I come in？ 在使用这一用法时需注意: may表示”允许”的否定形式是must not，意思是”不应该”“不许可”。 例如：May I take this book out of the reading-room？No，you mustnt不行。 b. 表示说话人的猜测，认为某一事情”或许”或”可能”发生。 例如：He may know the answerTomorrow I may go shopping c. may用在感叹句中可表示祝愿、愿望。 例如：May you succeed(祝你成功。)May you have a pleasant journey(一路平安。) 2. might的用法: a. might可以代替may，表示现在时间的动作，但语气较为婉转客气或更加不肯定。例如：He might not come todayMight I take a suggestion？ b. might用来表示现在时间时，还可表示”规劝”。 例如：You might pay more attention to spoken English 三. must与have to的区别have to比较强调客观需要，must着重说明主观看法。另外have to能用于更多时态，比较下面的句子： We had to be there at ten我们得在十点钟到那里。Well have to reconsider the whole thing这一切我将不得不重新加以考虑。 有时两者都可以用，意思差别不大。例如：We must have to leave now我们得走了。 must在表示说话人对事物的推测时候要注意它比may肯定得多，相当于汉语的”一定”或”准是”。（只有在肯定句中能这样用。） This must be your room There must be a mistake 在回答由must引起的问题时，如果是否定的答复，不能用mustnt，而需要用neednt或dont have to，因为mustnt是”一定不要”的意思。 例如：Must we hand in our exercises today？No，you neednt must not的否定形式则表示”不应该”或”不许可”，语气比较强烈。例如：You mustnt play on the roadYou mustnt eat anything until you see the doctorMust表猜测Must表肯定猜测：一定，肯定。例如：This book must be Wang Feis because her name is here.但一定不.不用mustnt， 而cant. 例如：The man cant be Mr Wang, I know he has gone to Shanghai.语法练习1. - Can you swim in the river?- No, I _.A. mustnt B. may not C. cant D. neednt2. - Excuse me. Where is the zoo?- Sorry, I dont know. Ask that policeman. He _ know.A. shall B. may C. need D. Would3. - Tom, where is your father?- Im not sure. He_ in his officeA. isB. may be C. maybe D. May4The book is on Lilys desk. _it is hers.A, Maybe B. May be C .Can D .Might5. This pair of shoes _ Deng Huas . Theyre too big for her.A. might beB. cant beC. must be6. .Its so cold and youve walked a long way. You _be tired. Have a rest. please. A .cant B. might C .must .C. can7.-Is Mr Hu in the reading room?-No,he _be there. He has gone to Tianjin.A. mustnt B. neednt C. wont D. cant8. -Whose book is this It _ be Lusys. Her name is on it. A .could B. cant C. must D. might9. - ay I go swimming now?- No, you _. You must finish your homework first.A. mustnt B. may not C. couldnt D. neednt10.- _ I finish the work today?- No, you neednt.A. Must B. May C. Can D. Need11. - Must I finish my homework now?- No, you _. You may have a rest first.A. mustnt B. cant C. may not D. neednt12. -_I visit Lucy on Sunday, Mum?-Yes, you_.A. Must；can B. May；may C. Need；need D. May；need13. Dad! Must I finish my homework first? -No, you_. You can do it after supper. A. mustnt B. needntC. cant D. couldnt14. There is an old saying. The cleverest housewife _cook a meal without rice.A. may B. mustnt C. neednt