1 . If fish are jumping higher than usual or frogs are croaking more loudly, it________ rain.

A．must

B．may

C．shall

D．need

2 . The designer has tried every possible way to make the robot light, so you_______worry about its weight.

A．must

B．may

C．can't

D．needn't

3 . —________ you leave now? You only arrived an hour ago!
—Sorry, but so much homework is waiting for me.

A．Must

B．May

C．Can

D．Might

4 . 面临气候变化带来的多重挑战，所有相关各方应保持联系，加强合作，共同应对由此产生的对生活方方面面的影响。 (contact) (汉译英)

5 . 尽管条件极其艰苦，我们必须坚持下去，直到成功。
We must ________ ________ till success in spite of the extremely difficult conditions.

6 . 选用适当的单词或短语补全对话
Boss: All the documents     1     （must/can） be prepared before the meeting starts
Secretary: I know that. Kelly has been working on the documents since last Monday. She     2    （may/must）have got everything ready but I am not sure.
Boss: Wheres Kelly then?
Secretary: She     3     （must/has to）be in the sales managers office now. I saw her go in there a minute ago.