1.It was raining hard _w_h_e_n___ I got home.
2.I was doing my homework _w_h__il_e__ my brother was playing games.
3.__A_s_ we walked, we talked. 4.We do not necessarily grow wiser _a_s_ we grow
6.since (from the time that)
• 句型：现在完成时 + since + 过去式 • I have worked here since I graduated from
the university.
• 句型：It is… since… • It is (has been) two years since he came
be doing…when…
I was having my supper when a friend of mine called in.
had done…when…
We had just crossed the street when someone called me.
be on one’s way…when…
The instant she saw him, she knew he was in love
with her. He left Europe the year World War Ⅱ broke out. 不需要使用when引导
2.Adverbial Clauses of Reason (原因状语从句）
here.
7. until, till, not…until
1.延续动词，用肯定形式，till/until… 表示动作或状态一 直持续到until/till所表示的时间：
We waited until he came. 2.瞬间动词，用否定形式，not…until… 意为“某动作直 到某时间才开始”。如：
5.After
After he (had) finished his work,he left there. He (had) finished his work before he left here. After finishing his work,he left here. Having finished his work,he left here.
older. 5._W_h_e_n_ I have finished, I’ll tell you. 6.He was just about to leave, _w__h_e_n__the telephone
rang.
7.She thought I was talking about her daughter, _w__h_il_e__ in fact, I was talking about my daughter.
(分词短语)
While walking in the street,he met Tim. Walking in the street ,he met Tim.
while也可做并列连词，表示对比的含义，意思为“然 而”，如： He is tall while his brother is short.
引导让步状语从句，表”虽然，尽管” = although While he is young, he has rich experience.
3.as
可以引导持续性动作，也可以引导瞬间性动作，表示主 句从句动作同时发生 As I stopped my car, a man came up to me.
9. every time, each time, any time, whenever 每次…就…；无论何时…就…
1) Every time/each time I catch a cold,I have pain in my back.
2) Whenever I see the picture , I can’t help thinking of my hometown.
3) When the lesson was over, we began our writing. (短暂性动作，从句动作在前）
在下列结构中，when作“在那时”讲，表示某件事正在 发生或刚刚发生时，这时另一动作发生…
be about to do…when…
She was about to start out when the telephone rang.
We were on our way to the station when we found a girl crying by the roadside.
be on the point of doing…when…
2.while
指“在某一时间里”，“在…期间”，从句里的动作必须 是持续性的，它也强调主句和从句动作的同时发生 While he was walking in the street, he met Tim.
“不到……就”
3． Please write it down before you forget it.
“趁……”
4． Before they reached the station, the train had
gone. “还没来得及”
before从句中谓语不用否定式。如： Before they reached the station, the train had
as soon as
一般现在时代替将来时 As soon as he comes back, I will let you know. 我一离开争吵就开始了. As soon as I left, the quarrel started. hardly/scarcely/barely…when… no sooner…than… 主句用过去完成时，从句用一般过去时
gone.
句型：
It will be long before sb does sth
要过很久某人才会……
It will be + 一段时间 + before sb does sth
某人要过多长时间才做……
It won’t be long before sb does sth
不用多久某人就会……
It was longΒιβλιοθήκη before sb did sth
过了很久某人才做…
It was + 一段时间 + before sb did. Sth
某人过了多长时间才做……
It won’t be long before he finishes his writing. It will be two years before he leaves the country. It wasn’t two years before he left the country.
I had hardly left when the quarrel started I had no sooner left than the quarrel started. 时态不同,主从句位置颠倒；主句倒装，从句不倒 Hardly had I left when the quarrel started. No sooner had I left than the quarrel started.
1.when
When即可引导持续性动作，又可引导短暂性动作。它可 以表示主句的动作和从句的动作同时发生，或从句的动作 发生在主句动作之前。
1) When he comes here tomorrow,I will call you. (短暂性动作，at the time that)
2) Henry is in charge of the office when Mr.Smith is away. (持续性动作，during the time that)
11. The moment The minute The instant Every time Each time The first time Next time
+主谓 引导时间状语从句 状从表示将来，用一般现在时态
I’ll tell you about it the moment you come.
2．从句动作发生在主句动作之前时，只能用when引导 这个从句，不可用as或while。 When you have finished your work, you may have a rest.
3．表示“随着……”，连词用as，不用when或while。 As the election approached, the violence got worse.
8.We were watching TV _w__h_e_n_ the light went out.
4.Before
1． We had sailed four days and four nights before
we saw land. “……才”
2． We hadn’t run a mile before he felt tired.
“一边…一边…” As they were picking tea,the girls were
singing happily. She sang as she worked.
“随着…” As the day went on, the weather got even cold.
连接词when, while, as的用法区别：
3) Every time he goes to town, he always visits his aunts