延续性动词，常理解为某一状态的终止；若用延续性动词或状态动词，则理解为某一动作的开始。since引导时间状语从句的常用句型：It is/has been＋时间段＋since...自从......以来多久了。

　　He has written to me frequently since I got sick.

　　自从我病了以后，他经常给我写信。

　　It is three years since he came to our school.

　　他来我们学校已经三年了。

　　It is three years since he smoked.

　　他戒烟已经三年了。

　　4．引导时间状语从句的名词词组

　　一些表示时间的名词词组，如the moment，every time，each time，the first time，the last time，the next time，the minute，the instant等可以用来引导时间状语从句，起连词的作用。

　　The moment I saw her，I knew there was something wrong.

　　我一看到她，我就知道出事了。

　　Every time I was in trouble，he would come to help me.

　　每次我处于困境，他就会来帮助我。

　　5．表示"一......就......"的引导词

　　as soon as，immediately，directly，instantly，the moment/minute/instant，no sooner ...than ...，hardly/scarcely ...when ...等都可引导时间状语从句，表示"一......就......"。

　　The boy burst into tears immediately he saw his mother.

　　这个男孩一看到他妈妈就放声大哭。

　　[名师点津]　

　　no sooner...than...；hardly...when...结构中，no sooner与hardly置于句首时，其后的句子用部分倒装。

　　No sooner had we arrived at the station than the train left.

　　我们一到车站，火车就离站了。

　　[即时训练1]

单句语法填空