时间状语从句PPT课件.

Judge the meanings of “as”.
1. As I left the house, I forgot the key.
2. As I get older, I get more optimistic. 3. He looked behind as he went. 4. As the weather is so bad, we have to stay home.
A．As
B．while
C．Because
D．If
连接词类别
作用 as 表示“当……的时候”，往往和 when/ while 通用，但它着重强调主句与从句的动作或事情同 时或几乎同时发生。
例句 1.She came up as I was cooking.（同时） 2.The runners started as the gun went off.（几 乎同时） 1.When we were at school, we went to the library every day.（在一段时间内） 2.Sorry，I was out when you called me．（ call为短暂性动词）对不起，你打电话时我 刚好外出了。 3. When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时， 客人们已经离开了。 1.When ／While ／As we were dancing，a stranger came in．（dance为延续性动词） 。 2.Please don’t talk so loud while others are working.
• While ,when 在句中的不同含义: While I was walking down the street, I came across an old friend. ( while=_______) While I really don’t like art, I find his work impressive. ( while =_________ ) He likes pop music, while I am fond of folk music. Strike while iron is hot.
me.
注意：before从句中谓语不用否定式。 Before they reached the station, the train had gone.
• 含有before的句型结构： 1. It will be / was＋一段时间＋before…“过多久才” • It_________________________(还要过两年)he leaves the country. • It ______________________(过了很长一段时间) before he got to sleep again. 2. It will be / was + not＋一段时间＋before… “不多久就……” • It wasn’t two years before he left the country. • It was not long before he came back.
5. You can do it as you like.
6. Old as he is, he is still energetic.
• Fill in the blanks with “when, while, as”
when you meet a word you don't know, consult the • 1______ dictionary. as • 2.The students took notes _____ they listened. As the wind rose ,the noise increased. • 3._____ while I was out. • 4.She called _______ • 5.We must strike while ______ the iron is hot. When • 6.________you have finished your work, you may have a rest. when she came into my room. • 7. I was just reading a book ______
1)They were walking down the street when they saw an accident. 2) I had just got home when it began to rain. 3) I was about to go swimming when our guide stopped me. 4) It's cold when it snows.
Adverbial Clauses
条件状语
结果状语
地点状语
目的状语
比较状语
方式状语 让步Hale Waihona Puke Baidu语 时间状语
原因状语
• 掌握状语从句的关键
1.准确掌握每一个连词的含义。 2.注意主句和从句的时态呼应。
(1) as , while , when • Which do you choose? －I′m going to the post office. －_____ you are there, can you buy me some stamps?
• before用法
1.We had sailed four days and four nights before we saw land. 2. We hadn’t run a mile before he felt tired. ……才 还没有/不到……就…… 3. Please write it down before you forget it.趁……（还未） 4. Before I could get in a word, he had measured 还没来得及……
as
when
when可以和延续性动词连用，也可以和短暂性动 词连用； when从句的谓语动词可以在主句谓语动作之前、 之后或同时发生；while和as从句的谓语动作必须 是和主句谓语动作同时发生。
while
从句动作和主句动作同时发生，且从句动作为延 续性动词时，(when，while，as都可使用)。 主句中的动作或事情是在从句中的动作或事情的 进展过程中发生，从句中的动词一般要用延续性 动词。