Unit 1 Section Ⅱ
Ⅰ.语法填空
1．—Must I hand in this paper one hour later?
—Yes，you __must__.
解析：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 __must__ have been very strong.
解析：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 __needn't__ do the exercise if you don't want to.
