4．他们本该午饭时间到达的，但他们的航班延误了。

They should have arrived at lunchtime but their flight was delayed.

5．你本没必要告诉我这个消息。我早知道了。

You needn't have told me the news.I have already known it.

Ⅰ.用情态动词和所给动词的正确形式填空

1．You ought to/should have given(give) him some advice.He was too upset at that time.

2．You mustn't smoke(smoke) in this part of the hospital.

3．There was plenty of time.She needn't have hurried(hurry)．

4．I have no bike，so I have to go(go) to the office on foot.

5．You needn't buy(not，buy) a gift，but you can if you want to.

6．Look！The road is wet.It must have rained(rain) last night.

7．Bob ought not to/should not speak(not，speak) to his mother like that.

8．You must come(come) here on time，or you'll be fined next time.

9．Hurry up！We ought to/should go(go) to school right away.

10．Her eyes are red.She must have been(be) crying.

Ⅱ.用"情态动词＋have done"完成句子

1．他们一定去过长城，不是吗？

They must have been to the Great Wall，haven't they?

2．昨天晚上他不可能看电视，因为他知道就要考试了。

He can't/couldn't have watched TV last night，for he knew he would have a test.

3．本来他能够通过考试，但是他太粗心了。

He could have passed the exam，but he was too careless.

4．以前你本应该多读书的。

You should/ought to have read more books before.

5．你可能已经在报纸上看过这个消息了。

You might/may have read about it in the newspapers.

6．我本不必做这么多吃的，大家都不饿。

I needn't have cooked so much food.Nobody was hungry.