1£®He is very humorous while his brother is very serious. That's where their difference lies.

2£®You'd better give the task to whoever you think can finish it ahead of time.

3£®—How come you are always staring at Jack this morning?

—He looks stupid! The way he wears his shirt is what annoys me most.

4£®I had neither a computer nor newspaper. That's why I don't know the latest news.

5£®A very old lady was badly hurt in what the police described as an apparently motiveless attack.

6£®He will talk to us about what he saw in the U£®S.A.

7£®Wang Hai told me why he didn't go hiking yesterday afternoon.

8£®I think it necessary that you should read English aloud.

9£®We're worried about whether he is safe or not.

10£®The question is which of us should come first.