【专题讲义】2020年中考英语一轮复习
专题33 时间状语从句知识点、考点及考题专题精讲（学生版）
1. 引导时间状语从句的连词
从属连词
用法
例句
While
＂与……同时，在……期间＂，从句常用延续性动词或表示状态的词
Don’t talk loud while(as)others are working.
别人工作时，请勿大声说话。
When
＂当……时＂，表示主句的动作和从句的动作同时或先后发生，从句的动词可用延续性动词，也可用非延续性动词
It was raining when we arrived.
我们到达时，天正下着雨。
when you read the poem a second time, the meaning will become clearer to you.
当你再读一遍这首诗，你就会更清楚它的含义。
As
＂正当，一边……一边，随着＂，表示两个动作同时发生或某事发生时，另一个动作发生了
As time went on, his theory proved to be correct.
随着时间的推移，他的理论被证明是正确的。
Till/Until
用于肯定句时，表示＂直到……为止＂，主句必须为延续性动词；not...until/till表示＂直到……才＂，主句常用短暂性动词
We shall wait until/till he comes back.
我们将一直等到他回来。
I didn’t leave until/till she finished her homework.
直到她完成作业我才离开。
Since
＂自……以来＂，主句用一般现在时或现在完成时，从句用一般过去时
I have heard lot of good things about you since I come back from abroad. 自从我从国外回来，我已经听许多好的事情。
Before
在……以前
He must finish all the work before he goes home.
回家之前他必须完成所有的工作。
After
在……之后
Let’s play football after school. 放学后我们打篮球吧。
【知识拓展】
时间状语从句的时态问题：在时间状语从句和条件状语从句中，主句如果使用一般将来时态，从句使用一般现在时表示将来，即所谓的＂主将从现＂。
As soon as I arrive in Beijing, I will ring you up. 我一到北京就给你打电话。
You’ll fall behind the others unless you study hard. 如果你不努力学习，你将会落后于其他人。
2. when，while，as引导时间状语从句的区别
when，while，as显然都可以引导时间状语从句，但用法区别非常大。
① when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。
Why do you want a new job when you’ve got such a good one already?
你已经找到如此好的工作，为何还想再找新的？ (get为短暂性动词)
Sorry, I was out when you called me.
对不起，你打电话时我刚好外出了。 (call为短暂性动词)
Strike while the iron is hot.
趁热打铁。 (is为延续性动词，表示一种持续的状态)
The students took notes as they listened.
学生们边听课边做笔记。 (listen为延续性动词)
② 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。
a. 从句动作在主句动作前发生，只用 when。
When he had finished his homework, he took a short rest. (finished先发生)
当他完成作业后，他休息了一会儿。
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。
b. 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。
①When / While / As we were dancing, a stranger came in. (dance为延续性动词)
当我们跳舞时，一位陌生人走了进来。
②When / While / As she was making a phonecall, I was writing a letter. (make为延续性动词)
当她在打电话时，我正在写信。
c. 当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时，as常表示＂随着……＂ ＂一边……，一边……＂之意。
As the time went on, the weather got worse. 随着时间的过去，天气变得更糟糕了。
The atmosphere gets thinner and thinner as the height increases.
随着高度的增加，大气越来越稀薄。
As years go by, China is getting stronger and richer.
随着时间一年一年过去，中国变得越来越富强了。
The little girls sang as they went. 小姑娘们一边走，一边唱。
The sad mother sat on the roadside, shouting as she was crying.
伤心的妈妈坐在路边，边哭边叫。
d. 在将来时的从句中，常用when，且从句要用一般时代替将来时。
You shall borrow the book when I have finished reading it.
在我读完这本书后，你可以借阅。
When the manager comes here for a visit next week, I’ll talk with him about this.
下周，经理来这参观时，我会和他谈谈此事。
③ when用于表示＂一……就……＂的句型中(指过去的事情)。
sb. had hardly(＝scarcely)done sth. when. . . ＝Hardly / Scarcely had sb. done sth. when...
I had hardly / scarcely closed my eyes when someone knocked at the door.
＝Hardly / Scarcely had I closed my eyes when someone knocked at the door.
我刚一闭上眼，就有人在敲门了。
I had hardly / scarcely entered my room when the telephone rang.
＝Hardly / Scarcely had I entered my room when the telephone rang.
我刚一走进房门，电话就响了。
3. 比较until和till
此两个连词意义相同。肯定形式表示的意思是＂做某事直至某时＂，动词必须是延续性的。否定形式表达的意思是＂直至某时才做某事＂。动词为延续性或非延续性都可以。正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。
肯定句：I slept until midnight. 我一直睡到半夜时醒了。
Wait till I call you. 等着我叫你。
(在肯定句中可用before代替。例如：Let’s get in the wheat before the sun sets.)
否定句：She didn’t arrive until 6 o’clock. 她直到6点才到。
Don’t get off the bus until it has stopped. 公共汽车停稳后再下车。
I didn’t manage to do it until you had explained how. 直到你教我后，我才会做。
区别：
(1)until可用于句首，而till通常不用于句首。
Until you told me, I had heard nothing of what happened.
直到你告诉我以前，出了什么事我一点也不知道。
(2)until when 疑问句中，until要放在句首。
—Until when are you staying?
—Until next Monday.
注意：否定句可用另外两种句式表示。
(3)Not until...在句首，主句用倒装。
Not until the early years of the 19th century did man know what heat is.
直到19 世纪初，人类才知道热为何物。
Not until I began to work did I realize how much time I had wasted.
直到工作，才认识到我已蹉跎了许多岁月。
(4)It is not until... that...
It was not until I began to work that I realized how much time I had wasted.
(5)表示＂一……就……＂的结构
hardly/scarcely... when/before, no sooner... than 和as soon as都可以表示＂一……就……＂的意思。
I had hardly / scarcely got home when it began to rain. 刚回家，就下起雨来了。
I had no sooner got home than it began to rain.
As soon as I got home, it began to rain.
注意：如果hardly, scarcely 或no sooner置于句首，句子必须用倒装结构。
Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
在下列各句的空格中填入适当的连词
1. ____________ he comes tomorrow, I shall ask where he has been.
2. ____________ he was speaking, everybody listened carefully.
3. I saw her just ____________ she was getting off the train.
4. Have a good look at that man ____________ you pass him.
5. It was already eight o’clock ____________ we got there.
6. I was about to go out ____________ a visitor came.
7. We’ll go to the country at the beginning of June, ____________ the summer harvest will start.
8. He learned to speak German ____________ he was in Berlin.
9. Henry is in charge of the office ____________ Mr. Smith is away.
10. I listen to the recorder ____________ I have time.
11. He had learned Chinese ____________ he came to China.
12. ____________ the work was done, we sat down to sum up experience.
13. I haven’t seen him ____________ he moved to the other side of the town.
14. I waited ____________ he came back.
15. It was not ____________ he took off his eyeglasses that I recognized him.
16. She likes everything to be in place ____________ she starts to work.
17. The thieves ran away ____________ they caught sight of the police.
18. They decided to go back home ____________ their money ran out.
19. We played outside till sunset, ____________ it began to rain.
20. ____________ I get to the airport, I will phone you to pick me up.
21. They were about to leave ____________ it began to rain.
22. He always stay in bed ____________ lunch time.
23. I like playing tennis ____________ my younger sister prefers watching ball games.
24. ____________ I understand your viewpoint, I don’t agree with you.
25. ____________ she grew older, she became more responsible.
1. 【2019 ? 黑龙江省大庆市】—Jim, let’s go out to play basketball.
—Oh, I won’t do that _________ I finish my homework.
A. if B. until C. because D. since
2. 【2019 ? 四川省广元市】They didn’t go home _________ they finished their work.
A. because B. when C. until
3. 【2019 ? 黑龙江省齐齐哈尔市】—The students of Grade 9 have to take part in the P. E. test.
—Yes, _________ you want to pass it and be stronger, practice more.
A. unless B. until C. if
4. 【2019 ? 贵州省贵阳市】Our eyesight will become poorer and poorer _________ we keep playing with phones.
A. though B. unless C. if
5. 【2019 ? 江苏省南通市】I still keep taking exercise every day I am busy with so many subjects.
A. until B. unless C. because D. though
6. 【2019 ? 四川省内江市】Cathy is afraid of the dog. She will run away _________ she sees it.
A. ever since B. although C. as soon as D. so that
7. 【2019 ? 江苏省无锡市】—The local food may taste a bit strange.
—Well, _________ we are here, why not give it a try?
A. though B. unless C. since D. because
8. 【2019 ? 江苏省镇江市】—Is your WeChat account (账户) safe?
—Yes, even my father can’t use it __________ I tell him the password.
A. when B. unless C. while D. if
9. 【2019 ? 云南省昆明市】__________ we continue to kill elephants for their ivory, we humans will lose them in the end.
A. If B. Before C. Until D. Although
10. 【2019 ? 青海省中考】The environment will be much worse __________ everyone has a sense of protecting it.
A. unless B. if C. so that
选词填空。
if, when, after, before, until
1. I went to bed __________ the TV program was over.
2. Kitty will go to a movie with me __________ she has free time.
3. Remember to close the windows __________ you go out.
4. You’d better finish your homework __________ you go to bed.
5. Mike didn’t know it __________ I told him.
二、单项选择。
1. (湖南省澧县2019届九年级下学期中考最后一次模拟)―Could you tell me when he ____________ back?
—Sure. He will come back as soon as he ____________ the classroom.
A. will come; finishes cleaning
B. comes; will finish cleaning
C. will come; will finish to clean
2. I’ll go to visit your uncle as soon as I ____________ Beijing.
A. get to B. will get to C. got to
3. Mr. Liu has taught us English ____________ he came to our school.
A. until B. because C. though D. since
4. (山东省龙口市兰高镇兰高学校2018届九年级上学期期中)My father was reading a newspaper ____________ my mother was cooking dinner.
A. when B. while C. as soon as D. Until
5. (山东省龙口市兰高镇兰高学校2018届九年级上学期期中)Many students didn’t realize the importance of study ____________ they left school.
A. when B. until C. as D. after
6. It’s been five years ____________ we met last time.
A. for B. when C. since D. if
7. A good storyteller must be able to hold his listeners’ curiosity(好奇心) ____________ he reaches the end of the story.
A. if B. unless C. after D. until
8. (江苏省句容市、丹阳市2017届九年级下学期中考网上阅卷第二次适应性检测)The TV programme The Readers (朗读者) was already over ____________ he got back home yesterday.
A. while B. until C. since D. when
9. —What were you doing ____________ the fire happened?
—I was watching TV at home.
A. if B. while C. when D. since
10. ____________ I saw the delivery man(快递员)cycling towards me, I knew that was my gift.
A. As B. Although C. Before D. While
【专题讲义】2020年中考英语一轮复习
专题33 时间状语从句知识点、考点及考题专题精讲（解析版）
1. 引导时间状语从句的连词
从属连词
用法
例句
While
＂与……同时，在……期间＂，从句常用延续性动词或表示状态的词
Don’t talk loud while(as)others are working.
别人工作时，请勿大声说话。
When
＂当……时＂，表示主句的动作和从句的动作同时或先后发生，从句的动词可用延续性动词，也可用非延续性动词
It was raining when we arrived.
我们到达时，天正下着雨。
when you read the poem a second time, the meaning will become clearer to you.
当你再读一遍这首诗，你就会更清楚它的含义。
As
＂正当，一边……一边，随着＂，表示两个动作同时发生或某事发生时，另一个动作发生了
As time went on, his theory proved to be correct.
随着时间的推移，他的理论被证明是正确的。
Till/Until
用于肯定句时，表示＂直到……为止＂，主句必须为延续性动词；not...until/till表示＂直到……才＂，主句常用短暂性动词
We shall wait until/till he comes back.
我们将一直等到他回来。
I didn’t leave until/till she finished her homework.
直到她完成作业我才离开。
Since
＂自……以来＂，主句用一般现在时或现在完成时，从句用一般过去时
I have heard lot of good things about you since I come back from abroad. 自从我从国外回来，我已经听许多好的事情。
Before
在……以前
He must finish all the work before he goes home.
回家之前他必须完成所有的工作。
After
在……之后
Let’s play football after school. 放学后我们打篮球吧。
【知识拓展】
时间状语从句的时态问题：在时间状语从句和条件状语从句中，主句如果使用一般将来时态，从句使用一般现在时表示将来，即所谓的＂主将从现＂。
As soon as I arrive in Beijing, I will ring you up. 我一到北京就给你打电话。
You’ll fall behind the others unless you study hard. 如果你不努力学习，你将会落后于其他人。
2. when，while，as引导时间状语从句的区别
when，while，as显然都可以引导时间状语从句，但用法区别非常大。
① when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。
Why do you want a new job when you’ve got such a good one already?
你已经找到如此好的工作，为何还想再找新的？ (get为短暂性动词)
Sorry, I was out when you called me.
对不起，你打电话时我刚好外出了。 (call为短暂性动词)
Strike while the iron is hot.
趁热打铁。 (is为延续性动词，表示一种持续的状态)
The students took notes as they listened.
学生们边听课边做笔记。 (listen为延续性动词)
② 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。
a. 从句动作在主句动作前发生，只用 when。
When he had finished his homework, he took a short rest. (finished先发生)
当他完成作业后，他休息了一会儿。
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。
b. 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。
①When / While / As we were dancing, a stranger came in. (dance为延续性动词)
当我们跳舞时，一位陌生人走了进来。
②When / While / As she was making a phonecall, I was writing a letter. (make为延续性动词)
当她在打电话时，我正在写信。
c. 当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时，as常表示＂随着……＂ ＂一边……，一边……＂之意。
As the time went on, the weather got worse. 随着时间的过去，天气变得更糟糕了。
The atmosphere gets thinner and thinner as the height increases.
随着高度的增加，大气越来越稀薄。
As years go by, China is getting stronger and richer.
随着时间一年一年过去，中国变得越来越富强了。
The little girls sang as they went. 小姑娘们一边走，一边唱。
The sad mother sat on the roadside, shouting as she was crying.
伤心的妈妈坐在路边，边哭边叫。
d. 在将来时的从句中，常用when，且从句要用一般时代替将来时。
You shall borrow the book when I have finished reading it.
在我读完这本书后，你可以借阅。
When the manager comes here for a visit next week, I’ll talk with him about this.
下周，经理来这参观时，我会和他谈谈此事。
③ when用于表示＂一……就……＂的句型中(指过去的事情)。
sb. had hardly(＝scarcely)done sth. when. . . ＝Hardly / Scarcely had sb. done sth. when...
I had hardly / scarcely closed my eyes when someone knocked at the door.
＝Hardly / Scarcely had I closed my eyes when someone knocked at the door.
我刚一闭上眼，就有人在敲门了。
I had hardly / scarcely entered my room when the telephone rang.
＝Hardly / Scarcely had I entered my room when the telephone rang.
我刚一走进房门，电话就响了。
3. 比较until和till
此两个连词意义相同。肯定形式表示的意思是＂做某事直至某时＂，动词必须是延续性的。否定形式表达的意思是＂直至某时才做某事＂。动词为延续性或非延续性都可以。正确使用这两个连词的关键之一就在于判断句中的动词该用肯定式还是否定式。
肯定句：I slept until midnight. 我一直睡到半夜时醒了。
Wait till I call you. 等着我叫你。
(在肯定句中可用before代替。例如：Let’s get in the wheat before the sun sets.)
否定句：She didn’t arrive until 6 o’clock. 她直到6点才到。
Don’t get off the bus until it has stopped. 公共汽车停稳后再下车。
I didn’t manage to do it until you had explained how. 直到你教我后，我才会做。
区别：
(1)until可用于句首，而till通常不用于句首。
Until you told me, I had heard nothing of what happened.
直到你告诉我以前，出了什么事我一点也不知道。
(2)until when 疑问句中，until要放在句首。
—Until when are you staying?
—Until next Monday.
注意：否定句可用另外两种句式表示。
(3)Not until...在句首，主句用倒装。
Not until the early years of the 19th century did man know what heat is.
直到19 世纪初，人类才知道热为何物。
Not until I began to work did I realize how much time I had wasted.
直到工作，才认识到我已蹉跎了许多岁月。
(4)It is not until... that...
It was not until I began to work that I realized how much time I had wasted.
(5)表示＂一……就……＂的结构
hardly/scarcely... when/before, no sooner... than 和as soon as都可以表示＂一……就……＂的意思。
I had hardly / scarcely got home when it began to rain. 刚回家，就下起雨来了。
I had no sooner got home than it began to rain.
As soon as I got home, it began to rain.
注意：如果hardly, scarcely 或no sooner置于句首，句子必须用倒装结构。
Hardly / Scarcely had I got home when it began to rain.
No sooner had I got home than it began to rain.
在下列各句的空格中填入适当的连词
1. ____________ he comes tomorrow, I shall ask where he has been.
2. ____________ he was speaking, everybody listened carefully.
3. I saw her just ____________ she was getting off the train.
4. Have a good look at that man ____________ you pass him.
5. It was already eight o’clock ____________ we got there.
6. I was about to go out ____________ a visitor came.
7. We’ll go to the country at the beginning of June, ____________ the summer harvest will start.
8. He learned to speak German ____________ he was in Berlin.
9. Henry is in charge of the office ____________ Mr. Smith is away.
10. I listen to the recorder ____________ I have time.
11. He had learned Chinese ____________ he came to China.
12. ____________ the work was done, we sat down to sum up experience.
13. I haven’t seen him ____________ he moved to the other side of the town.
14. I waited ____________ he came back.
15. It was not ____________ he took off his eyeglasses that I recognized him.
16. She likes everything to be in place ____________ she starts to work.
17. The thieves ran away ____________ they caught sight of the police.
18. They decided to go back home ____________ their money ran out.
19. We played outside till sunset, ____________ it began to rain.
20. ____________ I get to the airport, I will phone you to pick me up.
21. They were about to leave ____________ it began to rain.
22. He always stay in bed ____________ lunch time.
23. I like playing tennis ____________ my younger sister prefers watching ball games.
24. ____________ I understand your viewpoint, I don’t agree with you.
25. ____________ she grew older, she became more responsible.
1. 【2019 ? 黑龙江省大庆市】—Jim, let’s go out to play basketball.
—Oh, I won’t do that _________ I finish my homework.
A. if B. until C. because D. since
2. 【2019 ? 四川省广元市】They didn’t go home _________ they finished their work.
A. because B. when C. until
3. 【2019 ? 黑龙江省齐齐哈尔市】—The students of Grade 9 have to take part in the P. E. test.
—Yes, _________ you want to pass it and be stronger, practice more.
A. unless B. until C. if
4. 【2019 ? 贵州省贵阳市】Our eyesight will become poorer and poorer _________ we keep playing with phones.
A. though B. unless C. if
5. 【2019 ? 江苏省南通市】I still keep taking exercise every day I am busy with so many subjects.
A. until B. unless C. because D. though
6. 【2019 ? 四川省内江市】Cathy is afraid of the dog. She will run away _________ she sees it.
A. ever since B. although C. as soon as D. so that
7. 【2019 ? 江苏省无锡市】—The local food may taste a bit strange.
—Well, _________ we are here, why not give it a try?
A. though B. unless C. since D. because
8. 【2019 ? 江苏省镇江市】—Is your WeChat account (账户) safe?
—Yes, even my father can’t use it __________ I tell him the password.
A. when B. unless C. while D. if
9. 【2019 ? 云南省昆明市】__________ we continue to kill elephants for their ivory, we humans will lose them in the end.
A. If B. Before C. Until D. Although
10. 【2019 ? 青海省中考】The environment will be much worse __________ everyone has a sense of protecting it.
A. unless B. if C. so that
选词填空。
if, when, after, before, until
1. I went to bed __________ the TV program was over.
2. Kitty will go to a movie with me __________ she has free time.
3. Remember to close the windows __________ you go out.
4. You’d better finish your homework __________ you go to bed.
5. Mike didn’t know it __________ I told him.
二、单项选择。
1. (湖南省澧县2019届九年级下学期中考最后一次模拟)―Could you tell me when he ____________ back?
—Sure. He will come back as soon as he ____________ the classroom.
A. will come; finishes cleaning
B. comes; will finish cleaning
C. will come; will finish to clean
2. I’ll go to visit your uncle as soon as I ____________ Beijing.
A. get to B. will get to C. got to
3. Mr. Liu has taught us English ____________ he came to our school.
A. until B. because C. though D. since
4. (山东省龙口市兰高镇兰高学校2018届九年级上学期期中)My father was reading a newspaper ____________ my mother was cooking dinner.
A. when B. while C. as soon as D. Until
5. (山东省龙口市兰高镇兰高学校2018届九年级上学期期中)Many students didn’t realize the importance of study ____________ they left school.
A. when B. until C. as D. after
6. It’s been five years ____________ we met last time.
A. for B. when C. since D. if
7. A good storyteller must be able to hold his listeners’ curiosity(好奇心) ____________ he reaches the end of the story.
A. if B. unless C. after D. until
8. (江苏省句容市、丹阳市2017届九年级下学期中考网上阅卷第二次适应性检测)The TV programme The Readers (朗读者) was already over ____________ he got back home yesterday.
A. while B. until C. since D. when
9. —What were you doing ____________ the fire happened?
—I was watching TV at home.
A. if B. while C. when D. since
10. ____________ I saw the delivery man(快递员)cycling towards me, I knew that was my gift.
A. As B. Although C. Before D. While
1.?When??? 2.?While?/?When??? 3.?as???? 4.?when/as??? 5.?when?????
6.?when? ? 7.?when??? 8.?while?????? 9.?while?? 10.?whenever??
11.?before???? 12.?After?? 13.?since??? 14.?till/until????? 15.?until????
16.?before??? 17.?as?soon?as???? 18.?before ? 19.?when?? 20.?As?soon?as???
21. when??? 22.?until???? 23.?while???? 24.?While?? 25.?As?
1. B【解析】句意：——吉姆，我们出去打篮球吧。——哦，我要做完作业才能做那件事。A. if如果；B. until直到……为止；C. because因为；D. since自从。not…until直到……才……。until引导时间状语从句，故答案为B。
2. C【解析】考查连词用法。句意：他们直到完成作业才回家。A. because 因为；B. when 当……的时候； C. until直到。短语＂not…until＂意为＂直到……才……＂。根据空格前面didn’t可知用until，故选C。
3. C【解析】句意：——九年级的学生们必须参加体育考试。——是的，如果你想通过它更强壮，更多的练习吧。A. unless如果；B. until直到；C. if如果。根据practice more.可知，这里是if引导的条件状语从句，遵循主句是祈使句，从句用一般现在时态。根据题意，故选C。
4. C【解析】句意：如果我们继续玩手机，我们的视力会越来越差。A. though尽管，虽然；B. unless除非；C. if如果。这里是if引导的条件状语从句，遵循主句用一般将来时，从句用一般现在时态，根据题意，故选C。
5. D【解析】句意：尽管我忙于许多科目，但我仍然每天都在锻炼。A. until直到；B. unless 除非；C. because因为；D. though尽管。根据下文I am busy with so many subjects.可知这里是though引导的让步状语从句。根据题意，故选D。
6. C【解析】句意：凯西害怕狗，她一看到狗就跑了。考查连词辨析。A. ever since自从；B. although虽然、尽管；C. as soon as一……就……；D. so that以便；所以。根据Cathy is afraid of the dog. 凯西害怕狗，可推知是她一看到狗就跑开了，结合选项可知C选项符合题意，故答案选C。
7. C【解析】句意：——当地的食物可能有点奇怪。——既然我们在这里，为什么不尝尝呢？A. though尽管；B. unless除非；C. since既然；D. because因为。because语气最强，表示直接原因，可用于回答 why 提出的问题、引导表语从句、用于强调句等。since所表示的原因是人们已知的，即对已知事实提供理由，而不是表示直接原因。本题的why not give it a try? 为什么不尝尝呢？是因为当地的食物有点奇怪(间接原因)。而不是因为在当地，所以应该用since表达的间接原因。而不用because(直接原因)来引导。故选C。
8. B【解析】句意：——你的微信账号安全吗？——是的，如果我不告诉他密码甚至我的爸爸都不能使用它。when当……时候；unless除非，如果不；while当……时候；if如果。根据句意my father can’t use it…可知，这里应表示＂不告诉他密码＂，故应选B。
9. A【解析】句意：如果我们继续为了象牙猎杀大象，那么我们人类将会最终失去它们。A表示如果，B表示在……之前，C表示直到，D表示虽然、即使。根据题干可知如果我们继续为了象牙猎杀大象，那么我们人类终将会失去它们，句子前后是条件关系。故选A。
10. A 【解析】句意：除非每个人有保护环境的意识，否则环境将会更糟糕。A表示除非，B表示如果，C表示为了。根据题干可知除非每个人有保护环境的意识，否则环境将会更糟糕，本句是unless引导的条件状语从句。故选A。
一、选词填空。
1. after 2. if 3. when 4. before 5. until
二、单项选择。
1. A 【解析】句意：——你能告诉我他将什么时候回来吗？——当然可以。他一打扫完教室就会回来。本题第一句是宾语从句，第二句是时间状语从句。根据回答He will come back...可知，本题第一空用一般将来时；第二空主句是一般将来时，as soon as引导的时间状语从句用一般现在时。故选A。
2. A 【解析】句意：我一到北京就去看望你的叔叔。主句是一般将来时，as soon as引导的时间状语从句用一般现在时。故选A。
3. D 【解析】句意：Mr. Liu自从来到我们学校，就开始教我们英语。A. until直到……；B. because因为；C. though尽管；D. since自从。这里是since引导的时间状语从句，遵循主句用现在完成时，从句用一般过去时态。根据题意，故选D。
4. B 【解析】句意：我的父亲正在读报纸，而我的母亲正在做晚饭。when当……时候；while然而，表示两者进行对比；as soon as一……就……；until直到……。此处是我父亲和母亲所做的事进行对比，故用连词while。故选B。
5. B 【解析】句意：许多学生直到离开学校后才认识到学习的重要性。when当……时候；until直到……；as当……时候；after在……之后。not… until…＂直到……才……＂，故选B。
6. C 【解析】句意：自从我们上次见面已经5年了。for因为，为了；when当……时候；since自从；if如果。主句It’s been是It has been的缩写，是现在完成时态，since是自从的意思，引导时间状语从句，从句中用一般过去时态，主句用现在完成时，故选C。
7. D 【解析】句意：一个好的讲故事的人必须能够保持听者的好奇心，直到他到达故事的结尾。if如果，引导条件状语从句；unless除非，如果不；after在……之后；until 直到……时候。根据句意可知，讲故事的人应该保持听者的好奇心一直到故事讲完，故应选D。
8. D 【解析】句意：当他昨天回到家的时候，电视节目《朗读者》已经结束了。A.当……时候；B.直到……；C.自从；D.当……时候。因为get为瞬间动词，故选D。
9. C 【解析】句意：——火灾发生时你在干什么？——我在家看电视。A. if连词，如果，引导条件状语从句；B. while连词，当……时候，引导时间状语从句，谓语动词为延续性动词；C. when连词，当……时候，引导时间状语从句，谓语动词既是延续性动词也可是短暂性动词；D. since连词，自从，引导时间状语从句。happened暂时性动词，故选C。
10. A 【解析】句意：当我看到送货员骑着自行车向我跑来时，我知道那是我的礼物。A. As同时，当……时；B. Although尽管，表转折；C. Before在……之前，表时间；D. While与……同时，表时间。本句是时间状语从句，根据句意，BC两项与句意不合，可排除。as和while都可接时间状语从句，表示主句和从句的动作同时进行，但用法有别。如果主句和从句表示的是两个同时(或几乎同时)发生的短暂性(非持续性)动作，需用?as?/?when，而不可用while。结合句意和语境，可知选A。
