unit 1 第二课时
ⅰ.语法填空
1．—must i hand in this paper one hour later?
—yes, you________.
答案：must 句意：我必须一小时后交文件吗？——是的，必须。must可以表“推测”或“必须”，当表示“必须”时，肯定回答也必须用must。
2．—many boats near the seaside were destroyed by the wind.
—well, the wind ________ have been very strong.
答案：must 句意：——海岸附近的很多船都被风破坏了。——哦，那场风一定很大。can表示实际的可能性时，常用于否定句和疑问句中，用于否定句时，意为“不可能”；must表示接近事实的肯定推测，用于肯定句。
3．you ________ do the exercise if you don't want to.
答案：needn't 考查情态动词。句意：如果你不想运动，就不必做。needn't不必。
4．—isn't that your head teacher over there?
—no, it ________ be him. i'm sure he has just left.
答案：can't can't不可能。根据语境及答语中的“i'm sure”，可知答话的人肯定那不是校长。
5．when we lived in that village，we________ often climb mountains together.
答案：would 句意：当我们在那个村庄住的时候，我们经常一起爬山。would在此表示过去习惯性的动作。
6．a machine ________ work for itself; it must be operated by man.
答案：can't 句意：机器自己不能工作；必须有人操纵。can可以表示一种客观上的能力，本句can't，表示“不能，不会”。
7．you ________ leave the little boy alone at home. he is too young.
答案：mustn't 考查情态动词。句意：你不可以让小男孩单独待在家里，他太小了。mustn't绝不可以；needn't不必；mightn't可能不；won't不会。
8．how ________ you say that you really understand the whole text if you have covered only part of it?
