【正文】 mustn’t。12 Unit 3 Language in use 祈使句結(jié)構(gòu)如下： (Please) + do sth. (Please) + Don’t do sth. 肯定： 否定： DO，可以放在動詞前，為加強語氣用。 must D. must。 must C. can。 如： Do e in, please! Do listen to me, please! Do open the door, please! 一、我們已經(jīng)學(xué)習(xí)的表推測的情態(tài)動詞有： must/can/could/may/might 二、表推測的三種句式： 1. 在 肯定句中 一般用 must， can/could， may/might，程度逐漸減弱。 mustn’t。 can。 . He must/may/might know the answer to this question. . You have worked all this week. You must be tired. 2. 在 否定句 中用 can’t/couldn’t (不可能 )， may not/ might not(可能不 )。 can 5. –Look, someone is ing. Guess______ . Jack. He’s always on time. A. who can it be B. who he may C. who he can be D. who it can be A D 6. –I saw Mary in the library yesterday. You_____ her. She is still abroad. A. mustn’t see B. can’t have seen C. mustn’t have seen D. couldn’t see 7. David, you _____play with the valuable bottle, you_______ break it. A. won’t。 must B. can。 . It can’t /couldn’t be the headmaster. He has gone to America. . He may not/might not know the scientist. 3. 在 疑問句 中，一般只使用 can/could。 can’t B. mustn’t。 can’t。 . Could he have finished the task? . Can he be at home now? Language practice That could be harmful! Betty, you must know! Stay away from windows and heavy furniture. Do not stand near street lights or under power lines. 1. It is dangerous. You ________keep out! 2. These stairs are not safe. You _______use them. 3. The rocks are falling down. You ______get hit. 4. The