容光-microwave
When
的用法
4
种
1. When 即可以引导一个持续性动作，又可引导一个短暂性动作。可用以表示主从
句动
作同时发生或从句动作先于主句。 (既可引导时间点又可引导时间段)
I was
thin when I was a child.
The film had been on
when we arrived.
2. be about to do … when …
be doing …when…
be on one’s way
… when …
be on the point of doing …when…
had done … when…
“
在那时”“这时”,表示某件事正在发生或刚刚发生，另一动作同时发生
The
telephone was ringing when I got home.
I was
about to go to bed when he came back.
We were
just on the point of calling you up when you came
in.
3. When 还以引导条件状语从句相当于if
How can I
explain it to you when if you won’t listen.
How can you get good records when you don’t
study?
When you read it again, the meaning
will become clearer to you.
还可引导原因状语从句，“既然”
It was foolish of you to take a taxi when you
could easily walk there in five minutes.
While
的用法 3种
1.
必须引导持续性动作，强调在一段时间内，主句和从句动作同时发生。
My mother was
cooking while I was doing my homework.
Please
don’t talk so loud while others are working.
2. “然而” 表示轻微转折, 两者对比。
I like watching TV
while he likes reading.
3.引导让步状语从句 “
虽然，尽管”
While I admit his good points, I can
see his shortcomings.
While it is difficult, I
will try my best.
As 的用法
1 As I left
the house , I forgot the key.我离开家时，忘记了带钥匙。
As
引导时间状语从句，强调动作并行发生，不指先后。
2. As I get older, I
get more optimistic.
随着年龄的增长，我变得更加乐观 “ 随着”
表示时间的推移。
3. He hurried home, looking behind as
he went.
他匆匆忙忙回家，边走边往后看。 “一边…一边…”
4 As he
was going out, it began to rain.
当他出去时开始下雨了
强调两个动作紧接着发生。
5. As a boy (When he was a boy),
he was hopeless at English.
当他是孩子时，就对英语失去了希望。As有时引导一个名词，相当于时间状语从句。
As
I get older, I get more optimistic. （时间）
Young
as he is , he knows a lot. （让步）
As he
wasn’t ready in time, we went without him. （原因 ）
Do as I told you. do as you like. （ 方式 ）
He is as old as me.(比较)
I’m happy as
long as you are happy. （条件）
1. (04北京春) We were
swimming in the lake ______ suddenly the storm
started.
A. when B. while C.
until D. before
2. (02上海) He was about to
tell me the secret ______ someone patted him on
the shoulder.
A. as B. until C.
while D. when
3. (05上海) He transplanted the
little tree to the garden ______ it was the best
time for it.
A. where B. when
C. that D. until
4. (05福建) －Did Jack come back
early last night?
－Yes. It was not yet
eight o’clock ____ he arrived home.
A.
Before B. when C. that D. until
（注：句型：It iswas + 点时间+when从句）
5. (06天津) The
cost of living in Glasgow is among the lowest in
Britain, ______ the quality of life is
probably one of the highest.
A. since
B. when C. as D. while
6.
(04年江苏) ______ I accept that he is not perfect, I
do actually like the person.
A. While
B. Since C. Before D. Unless
7. (06辽宁) He was about halfway through his
meal ______ a familiar voice came to his
ears.
A. why B. where C. when
D. while
Before 的用法 4种
1. 在…之前
2.
It will (not) be +时间段＋before＋从句
“ 过了多久就、才… ”
; “过不了多久就才…”
3. “还没来得及，就…”
4. “趁……”
1. Before they got to the bus stop, the bus
had gone. 在..前
2. It will be 5 years before
he returns to his motherland. 过多久才…
waited a
long time before he came out.过了多久就、才…
4. It
won’t be long before we meet again.过不了多久就
5.
He died before he wrote a will. 还没来得及
6. Catch
him before he escapes. 还没来得及
7. Please write
it down before you forget it.趁着
1. (03年北京) He
made a mistake, but then he corrected the
situation ______ it got
worse.
A. until B. when C.
before D. as
2. (04福建) Scientists say it may
be five or six years______ it is possible to test
this
medicine on human patients.
A.
since B. after C. before D. when
3.
(06四川)－Why didn’t you tell him about the meeting?
－He rushed out of the room____I could say a
word.
A. before B. until C. when D.
after
till, until和not…until：
ill引导时间状语从句用于肯定句时，主句的动词
是延续性动词，表示动作或
状态一直持续到untiltill所
表示的时间，意为“某动作一直延续到某时间点才停止”。
如：We waited
untiltill he came.
2．用于否定句时，主句谓语动词是非延续性动词，从句为
肯定，意为“某动作直到某
时间才开始”。如：He won’t go to bed
tilluntil she returns.
3．till不可以置于句首，而until可以。如：Until you told me I
had no idea of it.
4．not…until句型中的强调和倒装说法：
It was not until you told me that I had any
idea of it.
Not until you told me did I have
any idea of it.
1 (03北京春) －Was his father very
strict with him when he was at school?
－Yes. He had never praised him ______ he became
one of the top students in his
grade.
A. after B. unless C. until D. when
2. (03上海) A good storyteller must be able to
hold listeners’ curiosity ______ he reaches
the end of the story.
A. when B.
unless C. after D. until
3. It was not
______ she took off her dark glasses______ I
realized she was a famous film
star.
A. when; that B. until; that
C.
until; when D. when; then
Mr li has been
here since 1998.
Mr li has been here since he
came back.
It’shas been two years since we
arrived here.我们到这儿两年了。
It is three years since
he lived here. (延续）
他不在这儿住三年了。
It is two
years since he smoked . (延续）
他不吸烟已有两年了。
It is two years since he began to smoke.
（非延续性v) 他开始吸烟有两年了。
1. （05北京春) It is almost
five years ______ we saw each other last time.
A. before B. since C. after D.
because
2. That was really a
splendid evening. It’s years _____ I enjoyed
myself so much.
A. when B. that C.
before D. since
表示“一……就……”的句型
1.
As soon as , once
2. Immediately, directly
3. The moment
4. On doing sth. 或者on one’s
+n.
5. No sooner …than
Hardly
…when…
Scarcely …when…
.1 As soon as
he arrives, I will tell him.
2. Once you work
hard, you will pass the exam.
3. The moment I
saw him, I recognized him.
4. I left
immediately the clock struck 5.
5. On hearing
the news, he cried.
6. On his arrival at the
classroom, the teacher came in .
7. Hardly had
I got home when it began to rain.
8. No sooner
had I got home than it began to rain.
一些含有time的名词短语和介词短语可以引导时间状语从句，如every time, each
time,
next time, any time the first (second,
last…)time, by the time, from the time等，以及the
day, the year, the week the morning等.
1. The day he returned home, his father was
already dead.
2. Next time you come, please
bring your composition
3. The first time I
climbed onto the wall, I felt nervous.
4. You
are welcome to come back any time you want to .
欢迎你随时回来。
5. The truck will have arrived by
the time you have all the things packed up.
到你把所有东西都捆好的时候，卡车也就来了。
6. By the time he
arrived, the train had already gone.
1.
(01北京春)－Did you remember to give Mary the money
you owed her?
－Yes. I gave it to her
______ I saw her.
A. while B. the
moment C. suddenly D. once
2. (1998上海) I
thought her nice and honest ______ I met her.
A. first time B. for the first time
C. the first time D. by the first
time
3. ______ entered the office when he
realized that he had forgotten his report.
A. He hardly had B. Had he hardly
C. Hardly had he D. Hardly he had