状语从句

　　状语从句可以用来表示时间、地点、条件、原因、目的、结果、行为方式、比较、让步等。

　　1)时间状语从句

　　常用的关联词有when， whenever， before， after， while， as， once(一旦)，until， (ever) since， as soon as等。时间和条件状语从句中表示将来的情况通常用一般现在时。如：

　　When you cross a road， you must be careful.

　　It will not be long before we meet again.

　　She comes here every month since she was a child to see her grandmother.

　　As soon as I know it， I'll tell you.

　　2)地点状语从句

　　关联词有 where 和 wherever.如：

　　Sit down wherever you like.

　　Put it where you found it.

　　3)条件状语从句

　　关联词有if， unless， as / so long as(只要)，in case(万一)等。如：

　　As/So long as we don't give up， we are bound to succeed.(be bound to do sth. 注定要做某事;give up 放弃)

　　In case I gorget， please remind me of that.(remind sb. of sth. 提醒某人做某事)

　　If it snows tomorrow， we will stay at home.

　　I will do anything as long as it is interesting.

　　4)原因状语从句

　　关联词有because， as(由于，因为)， since(由于，既然)，now that(既然)，that等。

　　As I didn't know the way， I asked a policeman.

　　Since no one is against， we'll adopt the proposal.

　　Seeing that she's ill， she's unlikely to come.

　　Not that I dislike the work， but that I have no time.