●叙述、询问理由

　　I forgot to lock the door.

　　Why? /How come? *比why?还要口语

　　I didn't like the movie. --How come?

　　I think she's in love with you.

　　What makes you think that?怎会那么想呢?

　　Why do you say that?

　　Why do you think that?

　　Tell me why.

　　What's the reason? 理由是什么?

　　My car broke down.

　　How did it happen? 怎么回事?

　　How did that happen?

　　What are you doing this for?

　　Why are you doing this?

　　What's the reason you're doing this?

　　Why are you doing something like this?

　　Why did you do that?

　　I didn't know I wasn't supposed to. 我不知道不能这样做

　　What made you do that?

　　Why did you do something like that?

　　How could you? /How could u do that?

　　The river is getting dirty.

　　What causes it? / What is it caused by?

　　Air pollution.

　　Explain it to me.

　　You'd better start explaining.

　　You can't wear the red pants. 裤子

　　Why not? They're my favorite.

　　Why can't I?

　　Is there a reason?

　　What are you so happy about?

　　It's a wonderful day.

　　You seem especially happy today.

　　What makes you so happy?

　　I made this big box!

　　What for? /For what? / What is this for? 干什么用? 因为什么?

　　I bought this gift today.

　　For who? /Who is it for?

　　What's the purpose of your visit?

　　What brought you here? 为什么来这儿?

　　Why do you want to do that?

　　No reason not to. /Why shouldn't I? /Why not? /What's wrong with it? 为什么不