時(shí)間狀語從句

　　1)在帶有till或until引導(dǎo)的時(shí)間狀語從句的主從復(fù)合句里，如果主句用肯定式，其含義是“一直到……時(shí)”，謂語動(dòng)詞只能用延續(xù)性動(dòng)詞。如果主句用否定式，其含義是“直到……才……”, “在……以前不……”, 謂語動(dòng)詞可用瞬間動(dòng)詞。例如：

　　The young man read till the light went out.

　　Let’s wait until the rain stops.

　　We won’t start until Bob comes.

　　Don’t get off until the bus stops.

　　2)時(shí)間狀語從句常用when, as, while, before, after, since, till, until, as soon as等連詞來引導(dǎo)。例如：

　　It was raining hard when got to school yesterday.

　　While he was doing his homework, the telephone rang.

　　As he walked along the lake, he sang happily.

　　He had learned a little Chinese before he came to China.

　　After he finished middle school, he went to work in a factory.

　　3)在時(shí)間狀語從句里，通常不用將來時(shí)態(tài)，用現(xiàn)在時(shí)態(tài)表示將來的動(dòng)作或狀態(tài)。例如：

　　I’ll ring you up as soon as I get to New York.

　　I will tell him everything when he comes back.

　　He won’t believe it until he sees it with his own eyes.