Ⅰ.用must、can、can’t或 may完成句子。
1. You be tired after hiking for three hours. Let’s take a rest.
2. The sky is dark and cloudy. It rain this evening.
3. This is my favourite novel. You keep it for a week if you like it.
4. You be serious. The phone is too expensive for us to afford.

1. must
2. may
3. can/may
4. can't

Ⅱ.用must、can、can’t、may或might补全对话,部分空格答案不唯一。
Amy: Look! There is a poor little cat over there. It looks very weak and it is shaking all over. It 1. be very hungry and cold. Let's go and help it.
Lisa: Wait, don't touch it! It 2. be a pet cat with an owner, because it looks dirty and scared.
Amy: Why 3. we get close to it? We can't just leave it alone even if it seems like a stray cat (流浪猫).
Lisa: It 4. carry some viruses and spread diseases. It's not safe for us.
Amy: Then what can we do? There 5. be something we can do for it.
Lisa: We 6. give it some food and clean water first, and then we can ask the animal centre for help.

1. must
2. can't
3. can't
4. may/might
5. must
6. can