1 . One__________ as hard as one can at a young age before it becomes too late.

A．might have worked	B．ought to work
C．would work	D．must have worked

2 . 我的姐姐回家时满脸笑容。她一定通过驾照考试了。(情态动词 + have done)
My sister came home with a broad smile on her face. She ____________________________.

3 . 他如此见多识广,一定去过很多地方且读过很多书。(well-informed;情态动词 + have done) (汉译英)

4 . 我们一定是走错路了，因为道路变窄了。(must have done)
________, because the road became narrow.

5 . 既然没有人帮助他, 他一定是独自完成了这项研究。(must have done)
Since nobody gave him any help, he ________.

6 . —That lecture was a boring and confusing one.
—Then it       Dr. Kevin’s because he is so interesting and fascinating. It       Dr. Jaco’s, he is just that type of person.

A．couldn’t have been…must be	B．couldn’t be…can be
C．mustn’t be…can’t be	D．can’t have been…must have been

7 . 这座古堡一定在火灾中被烧毁了，因为我们在它原来所在的地方看到的只有灰烬。
The ancient castle ________ ________ ________ ________ ________ in the fire, for we saw nothing but ashes where it used to be. (burn)

8 . 他一定已经完成家庭作业了，否则他是不会跟我们一起踢足球的。（must have done）（汉译英）