語(yǔ)法講解：時(shí)間狀語(yǔ)從句的用法解析及練習(xí)
狀語(yǔ)從句在復(fù)合句中作狀語(yǔ)，其位置較靈活，可以在主句之前、之后或中間(放在句首時(shí)狀語(yǔ)從句后面常用逗號(hào)，放在句末時(shí)狀語(yǔ)從句前面往往不用逗號(hào))。根據(jù)狀語(yǔ)從句的含義，狀語(yǔ)從句主要分為時(shí)間狀語(yǔ)從句、地點(diǎn)狀語(yǔ)從句、原因狀語(yǔ)從句、目的狀語(yǔ)從句、方式狀語(yǔ)從句、結(jié)果狀語(yǔ)從句、條件狀語(yǔ)從句、讓步狀語(yǔ)從句等八種。掌握以上各種狀語(yǔ)從句的關(guān)鍵在于把握其相應(yīng)的引導(dǎo)詞。以下是對(duì)時(shí)間狀語(yǔ)從句的基本用法進(jìn)行小結(jié)，希望可以幫助到同學(xué)們有一更深的理解。
時(shí)間狀語(yǔ)從句的引導(dǎo)詞
when, before, after, as, while, till/until, since，whenever
時(shí)間狀語(yǔ)從句的用法
時(shí)間狀語(yǔ)從句的引導(dǎo)詞所表示的意思不盡相同，要注意把握不同的時(shí)間狀語(yǔ)從句的引導(dǎo)詞所表示的不同時(shí)間關(guān)系，以及它在具體句子中對(duì)應(yīng)的對(duì)應(yīng)時(shí)態(tài)、語(yǔ)態(tài)等問(wèn)題。
1. when、as、while引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
(1) when引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)?shù)臅r(shí)候，when既可以指時(shí)間段也可指時(shí)間點(diǎn)，從句中既可用延續(xù)性動(dòng)詞又可用非延續(xù)性動(dòng)詞，且動(dòng)作既可和主句的動(dòng)作同時(shí)發(fā)生又可在主句的動(dòng)作之前或之后發(fā)生。
注意體會(huì)如下例句：Ill call you when I get there. 我一到那里就給你打電話。// When the wind blows, all the doors rattle. 只要風(fēng)一吹，這門就吱嘎作響。// He stopped trying, when he might have succeeded next time. 他不再試了，其實(shí)他可能下一次就成功。// When I came home my wife was cooking dinner. 我回家時(shí)，妻子在做晚飯。
如果when引導(dǎo)的時(shí)間狀語(yǔ)從句的主語(yǔ)與主句主語(yǔ)相同，而從句的謂語(yǔ)又是be動(dòng)詞時(shí)，那么從句中的主語(yǔ)和be可以省略;當(dāng)when引導(dǎo)的時(shí)間狀語(yǔ)從句的主語(yǔ)與主句主語(yǔ)相同時(shí)，往往還可以用when+分詞的形式替代該狀語(yǔ)從句。例如：When (you are) in trouble, ask her for help. 當(dāng)你遭遇麻煩的時(shí)候去向她求助。// When I came into the room (=When coming into the room), I found him lying there asleep. 當(dāng)我進(jìn)入房間的時(shí)候，我發(fā)現(xiàn)他躺在那兒睡著了。
(2) while引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)?shù)臅r(shí)候，它強(qiáng)調(diào)主句的動(dòng)作與從句的動(dòng)作同時(shí)持續(xù)地進(jìn)行，用于這一用法時(shí)while引導(dǎo)的時(shí)間狀語(yǔ)從句和主句中的謂語(yǔ)動(dòng)詞必須是延續(xù)性動(dòng)詞，或者主句的動(dòng)作發(fā)生在從句動(dòng)作的進(jìn)行過(guò)程中，主句中的謂語(yǔ)動(dòng)詞通常是非延續(xù)性動(dòng)詞，例如：Study while you study; play while you play. 該學(xué)習(xí)的時(shí)候就學(xué)習(xí)，該玩的時(shí)候就玩。// I met her while I was at school. 當(dāng)我在學(xué)校的時(shí)候我遇見了她。
(3) as引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)時(shí)，一邊一邊，側(cè)重表示兩個(gè)動(dòng)作同時(shí)發(fā)生(包括一個(gè)主語(yǔ)同時(shí)進(jìn)行兩個(gè)動(dòng)作)，或者一種動(dòng)作隨著另一種動(dòng)作的變化而變化。例如：He jumps as he goes along. 他邊走邊跳。// I slipped on the ice as I ran home. 我跑回家時(shí)在冰上滑了一跤。// I saw him as he was getting off the bus. 正當(dāng)他下公共汽車時(shí), 我看見了他。// As the wind rose the noise increased. 刮風(fēng)的時(shí)候噪聲增大。
[考題1] I had just steeped out of the bathroom and was busily drying myself with a towel ____ I heard the steps.
A. while B. when C. since D. after
[答案] B
[解析] 下劃線處表示 正在這時(shí)，突然，四個(gè)選項(xiàng)中只有when可以表示此含義。
[考題2] He was about halfway through his meal ____ a familiar voice came to his ears.
A. why B. where C. when D. while
[答案] C
[解析] 下劃線處表示 正在這時(shí)，突然，四個(gè)選項(xiàng)中只有when可以表示此含義。
[考題3] We were swimming in the lake ____ suddenly the storm started.
A. when B. while C. until D. before
[答案] A
[解析] 題意為當(dāng)我們正在湖里游泳的時(shí)候突然暴風(fēng)雨開始了，表示主句的動(dòng)作處于從句的動(dòng)作突然發(fā)生時(shí)應(yīng)采用when(while不適合用于這樣的語(yǔ)境)，when表示當(dāng)?shù)臅r(shí)候受限制條件最少。
[考題4] Im going to the post office.
____ youre there, can you get me some stamps?
A. As B. While C. Because D. If
[答案] B
[解析] 主句中g(shù)et me some stamps的動(dòng)作發(fā)生在時(shí)間狀語(yǔ)從句youre there的過(guò)程之中，因此應(yīng)選while表示這一時(shí)間關(guān)系(屬于while引導(dǎo)時(shí)間狀語(yǔ)從句的兩大基本用法之一)。因此B選項(xiàng)是最佳選項(xiàng)。
注意：如果主句的動(dòng)作發(fā)生于表示當(dāng)時(shí)的時(shí)間狀語(yǔ)從句中的動(dòng)作的進(jìn)行過(guò)程中，從句常用進(jìn)行時(shí)。例如：The landlady suspected that someone must have broken into the house when/while/as she was watching TV show. 女房東懷疑在她看電視時(shí)曾有人闖入屋里。// When/While/As Tom was reading, Jim was arrested. 在湯姆看書的時(shí)候，吉姆被逮捕了。
[考題5] I ____ along the street looking for a place to park when the accident ____.
A. went; was occurring B. went; occurred
C. was going; occurred D. was going; had occurred
[答案] C
[解析] 根據(jù)題干句子含義，事故發(fā)生于當(dāng)我沿街行駛、尋找停車之處的時(shí)候;從句的動(dòng)作發(fā)生在主句動(dòng)作的過(guò)程中。主句的謂語(yǔ)動(dòng)詞go表示非延續(xù)性的動(dòng)作，可以持續(xù)進(jìn)行，應(yīng)選用過(guò)去進(jìn)行時(shí)的形式，從句的謂語(yǔ)動(dòng)詞為非延續(xù)性動(dòng)詞，應(yīng)以一般過(guò)去時(shí)的形式表結(jié)果。
2. before和after 引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
before引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示主句的動(dòng)作發(fā)生在從句動(dòng)作之前，after引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示主句的動(dòng)作發(fā)生在從句動(dòng)作之后。例如：See me before you leave. 在你離開之前來(lái)見我。// Before they drive any of the buses, they will have to pass a special test. 在駕駛公共汽車之前，他們必須通過(guò)專門測(cè)驗(yàn)。// I saw them after I arrived. 在我抵達(dá)之后，我見到了他們。// I found his pen after he has left. 在他走后，我找到了他的筆。
[考題6] He was told that it would be at least three more months ____ he could recover and return to work.
A. when B. before C. since D. that
[答案] B
[解析] 表示他康復(fù)并返回工作崗位之前至少還需要三個(gè)月，下劃線處應(yīng)選用before。
[考題7] It was some time ____ we realized the truth.
A. when B. until C. since D. before
[答案] D
[解析] 題干意為：過(guò)了一段時(shí)間我們才意識(shí)到真相。下劃線處應(yīng)填入表示在之前的連詞。
3. till和 until 引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
till和 until這兩個(gè)詞作連詞和介詞時(shí)的意義和用法相同，一般可以換用(放在句首時(shí)通常用until的形式，till在口語(yǔ)中更為常見)。till和 until引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)跟主句里肯定形式或否定形式的、表示延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用表示到為止，跟主句里否定形式的、表示非延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用表示直到才(開始)，例如：Walk till you come to a white house. 一直走到一座白房子為止。// We didnt discuss the problem until he came back. 我們一直等到他回來(lái)后才討論問(wèn)題。
[考題8] It is difficult for us to learn a lesson in life ____ weve actually had that lesson.
A. until B. after C. since D. when
[答案] A
[解析] 題干的句子可以直譯為：在我們一生中，學(xué)到某個(gè)教訓(xùn)是困難的，直到我們真正經(jīng)歷了這個(gè)教訓(xùn)為止。
[考題9] A good storyteller must be able to hold his listeners curiosity ____ he reaches the end of the story.
A. when B. unless C. after D. until
[答案] D
[解析] 講故事的人應(yīng)該始終抓住聽眾的好奇心，本題應(yīng)選用表示到為止(跟主句里肯定形式的表延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用)的until 表示這一時(shí)間關(guān)系。
[考題10] I dont really work here; I ____ until the new secretary arrives.
A. just help out B. have just helped out
C. am just helping out D. will just help out
[答案] C
[解析] I dont really work here表明說(shuō)話人只是臨時(shí)前來(lái)幫忙，until the new secretary arrives表明說(shuō)話人，工作到新秘書就任為止，本題應(yīng)選用表示到為止(跟主句里肯定形式的表延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用)的until表示這一時(shí)間關(guān)系。
4. since引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
since引導(dǎo)的時(shí)間狀語(yǔ)從句表示自從以來(lái)，其用法主要有兩種：
(1) 現(xiàn)在完成時(shí)的主句+since引導(dǎo)的一般過(guò)去時(shí)態(tài)的時(shí)間狀語(yǔ)從句。例如：He hasnt been home since he graduated. 他畢業(yè)后沒回過(guò)家。// They have been friends ever since they were in grade school. 他們從小學(xué)起就一直是好朋友。// What have you been doing since I last saw you? 自我上次和你見面以后，你在做什么?
(2) It be(主句中謂語(yǔ)用一般式和用完成式區(qū)別不大，后者更具強(qiáng)調(diào)意味)+表示一段時(shí)間的詞匯+since引導(dǎo)的時(shí)間狀語(yǔ)從句。例如：It is two years since I became a postgraduate student. 我成為研究生已經(jīng)有2年了。It was three years since we had been there. 我們?cè)谀莾阂汛袅巳辍?/p>
注意：since做介詞時(shí)也表示自從以來(lái)，其具體用法有兩種情況：
(1) since+表示過(guò)去某個(gè)時(shí)間點(diǎn)的詞匯(如具體的年、月、日期、鐘點(diǎn))。
例如：They have been friends since childhood. 他們從幼時(shí)起一直是好朋友。Shes been skiing since childhood. 她從幼時(shí)起就開始滑雪。I have been there many times since the war. 自那次戰(zhàn)爭(zhēng)以來(lái)，我曾去該地多次。
(2) since+表示一段時(shí)間的詞匯+ago。
例如：I have been here since five months ago. 五個(gè)月以來(lái)我一直在這里。
[考題11] They ____ friends since they met in Shanghai.
A. have made B. have become C. have been D. have turned
[答案] C
[解析] 題干中的since表示自從以來(lái)，主句中的謂語(yǔ)動(dòng)詞應(yīng)該表示從他們?cè)谏虾Ｏ嘤鲋两竦某掷m(xù)性的動(dòng)作，因此下劃線處應(yīng)填入可以表示持續(xù)性狀態(tài)的have been(其他選項(xiàng)中的made、become、turned所表示的動(dòng)作都不能延續(xù)，意味著結(jié)果)。
[考題12] What was the party like?
Wonderful. Its been 2 years ____ I enjoyed myself so much.
A. after B. before C. when D. since
[答案] D
[解析] since表示自從以來(lái)。
狀語(yǔ)從句在復(fù)合句中作狀語(yǔ)，其位置較靈活，可以在主句之前、之后或中間(放在句首時(shí)狀語(yǔ)從句后面常用逗號(hào)，放在句末時(shí)狀語(yǔ)從句前面往往不用逗號(hào))。根據(jù)狀語(yǔ)從句的含義，狀語(yǔ)從句主要分為時(shí)間狀語(yǔ)從句、地點(diǎn)狀語(yǔ)從句、原因狀語(yǔ)從句、目的狀語(yǔ)從句、方式狀語(yǔ)從句、結(jié)果狀語(yǔ)從句、條件狀語(yǔ)從句、讓步狀語(yǔ)從句等八種。掌握以上各種狀語(yǔ)從句的關(guān)鍵在于把握其相應(yīng)的引導(dǎo)詞。以下是對(duì)時(shí)間狀語(yǔ)從句的基本用法進(jìn)行小結(jié)，希望可以幫助到同學(xué)們有一更深的理解。
時(shí)間狀語(yǔ)從句的引導(dǎo)詞
when, before, after, as, while, till/until, since，whenever
時(shí)間狀語(yǔ)從句的用法
時(shí)間狀語(yǔ)從句的引導(dǎo)詞所表示的意思不盡相同，要注意把握不同的時(shí)間狀語(yǔ)從句的引導(dǎo)詞所表示的不同時(shí)間關(guān)系，以及它在具體句子中對(duì)應(yīng)的對(duì)應(yīng)時(shí)態(tài)、語(yǔ)態(tài)等問(wèn)題。
1. when、as、while引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
(1) when引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)?shù)臅r(shí)候，when既可以指時(shí)間段也可指時(shí)間點(diǎn)，從句中既可用延續(xù)性動(dòng)詞又可用非延續(xù)性動(dòng)詞，且動(dòng)作既可和主句的動(dòng)作同時(shí)發(fā)生又可在主句的動(dòng)作之前或之后發(fā)生。
注意體會(huì)如下例句：Ill call you when I get there. 我一到那里就給你打電話。// When the wind blows, all the doors rattle. 只要風(fēng)一吹，這門就吱嘎作響。// He stopped trying, when he might have succeeded next time. 他不再試了，其實(shí)他可能下一次就成功。// When I came home my wife was cooking dinner. 我回家時(shí)，妻子在做晚飯。
如果when引導(dǎo)的時(shí)間狀語(yǔ)從句的主語(yǔ)與主句主語(yǔ)相同，而從句的謂語(yǔ)又是be動(dòng)詞時(shí)，那么從句中的主語(yǔ)和be可以省略;當(dāng)when引導(dǎo)的時(shí)間狀語(yǔ)從句的主語(yǔ)與主句主語(yǔ)相同時(shí)，往往還可以用when+分詞的形式替代該狀語(yǔ)從句。例如：When (you are) in trouble, ask her for help. 當(dāng)你遭遇麻煩的時(shí)候去向她求助。// When I came into the room (=When coming into the room), I found him lying there asleep. 當(dāng)我進(jìn)入房間的時(shí)候，我發(fā)現(xiàn)他躺在那兒睡著了。
(2) while引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)?shù)臅r(shí)候，它強(qiáng)調(diào)主句的動(dòng)作與從句的動(dòng)作同時(shí)持續(xù)地進(jìn)行，用于這一用法時(shí)while引導(dǎo)的時(shí)間狀語(yǔ)從句和主句中的謂語(yǔ)動(dòng)詞必須是延續(xù)性動(dòng)詞，或者主句的動(dòng)作發(fā)生在從句動(dòng)作的進(jìn)行過(guò)程中，主句中的謂語(yǔ)動(dòng)詞通常是非延續(xù)性動(dòng)詞，例如：Study while you study; play while you play. 該學(xué)習(xí)的時(shí)候就學(xué)習(xí)，該玩的時(shí)候就玩。// I met her while I was at school. 當(dāng)我在學(xué)校的時(shí)候我遇見了她。
(3) as引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示當(dāng)時(shí)，一邊一邊，側(cè)重表示兩個(gè)動(dòng)作同時(shí)發(fā)生(包括一個(gè)主語(yǔ)同時(shí)進(jìn)行兩個(gè)動(dòng)作)，或者一種動(dòng)作隨著另一種動(dòng)作的變化而變化。例如：He jumps as he goes along. 他邊走邊跳。// I slipped on the ice as I ran home. 我跑回家時(shí)在冰上滑了一跤。// I saw him as he was getting off the bus. 正當(dāng)他下公共汽車時(shí), 我看見了他。// As the wind rose the noise increased. 刮風(fēng)的時(shí)候噪聲增大。
[考題1] I had just steeped out of the bathroom and was busily drying myself with a towel ____ I heard the steps.
A. while B. when C. since D. after
[答案] B
[解析] 下劃線處表示 正在這時(shí)，突然，四個(gè)選項(xiàng)中只有when可以表示此含義。
[考題2] He was about halfway through his meal ____ a familiar voice came to his ears.
A. why B. where C. when D. while
[答案] C
[解析] 下劃線處表示 正在這時(shí)，突然，四個(gè)選項(xiàng)中只有when可以表示此含義。
[考題3] We were swimming in the lake ____ suddenly the storm started.
A. when B. while C. until D. before
[答案] A
[解析] 題意為當(dāng)我們正在湖里游泳的時(shí)候突然暴風(fēng)雨開始了，表示主句的動(dòng)作處于從句的動(dòng)作突然發(fā)生時(shí)應(yīng)采用when(while不適合用于這樣的語(yǔ)境)，when表示當(dāng)?shù)臅r(shí)候受限制條件最少。
[考題4] Im going to the post office.
____ youre there, can you get me some stamps?
A. As B. While C. Because D. If
[答案] B
[解析] 主句中g(shù)et me some stamps的動(dòng)作發(fā)生在時(shí)間狀語(yǔ)從句youre there的過(guò)程之中，因此應(yīng)選while表示這一時(shí)間關(guān)系(屬于while引導(dǎo)時(shí)間狀語(yǔ)從句的兩大基本用法之一)。因此B選項(xiàng)是最佳選項(xiàng)。
注意：如果主句的動(dòng)作發(fā)生于表示當(dāng)時(shí)的時(shí)間狀語(yǔ)從句中的動(dòng)作的進(jìn)行過(guò)程中，從句常用進(jìn)行時(shí)。例如：The landlady suspected that someone must have broken into the house when/while/as she was watching TV show. 女房東懷疑在她看電視時(shí)曾有人闖入屋里。// When/While/As Tom was reading, Jim was arrested. 在湯姆看書的時(shí)候，吉姆被逮捕了。
[考題5] I ____ along the street looking for a place to park when the accident ____.
A. went; was occurring B. went; occurred
C. was going; occurred D. was going; had occurred
[答案] C
[解析] 根據(jù)題干句子含義，事故發(fā)生于當(dāng)我沿街行駛、尋找停車之處的時(shí)候;從句的動(dòng)作發(fā)生在主句動(dòng)作的過(guò)程中。主句的謂語(yǔ)動(dòng)詞go表示非延續(xù)性的動(dòng)作，可以持續(xù)進(jìn)行，應(yīng)選用過(guò)去進(jìn)行時(shí)的形式，從句的謂語(yǔ)動(dòng)詞為非延續(xù)性動(dòng)詞，應(yīng)以一般過(guò)去時(shí)的形式表結(jié)果。
2. before和after 引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
before引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示主句的動(dòng)作發(fā)生在從句動(dòng)作之前，after引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)表示主句的動(dòng)作發(fā)生在從句動(dòng)作之后。例如：See me before you leave. 在你離開之前來(lái)見我。// Before they drive any of the buses, they will have to pass a special test. 在駕駛公共汽車之前，他們必須通過(guò)專門測(cè)驗(yàn)。// I saw them after I arrived. 在我抵達(dá)之后，我見到了他們。// I found his pen after he has left. 在他走后，我找到了他的筆。
[考題6] He was told that it would be at least three more months ____ he could recover and return to work.
A. when B. before C. since D. that
[答案] B
[解析] 表示他康復(fù)并返回工作崗位之前至少還需要三個(gè)月，下劃線處應(yīng)選用before。
[考題7] It was some time ____ we realized the truth.
A. when B. until C. since D. before
[答案] D
[解析] 題干意為：過(guò)了一段時(shí)間我們才意識(shí)到真相。下劃線處應(yīng)填入表示在之前的連詞。
3. till和 until 引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
till和 until這兩個(gè)詞作連詞和介詞時(shí)的意義和用法相同，一般可以換用(放在句首時(shí)通常用until的形式，till在口語(yǔ)中更為常見)。till和 until引導(dǎo)時(shí)間狀語(yǔ)從句時(shí)跟主句里肯定形式或否定形式的、表示延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用表示到為止，跟主句里否定形式的、表示非延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用表示直到才(開始)，例如：Walk till you come to a white house. 一直走到一座白房子為止。// We didnt discuss the problem until he came back. 我們一直等到他回來(lái)后才討論問(wèn)題。
[考題8] It is difficult for us to learn a lesson in life ____ weve actually had that lesson.
A. until B. after C. since D. when
[答案] A
[解析] 題干的句子可以直譯為：在我們一生中，學(xué)到某個(gè)教訓(xùn)是困難的，直到我們真正經(jīng)歷了這個(gè)教訓(xùn)為止。
[考題9] A good storyteller must be able to hold his listeners curiosity ____ he reaches the end of the story.
A. when B. unless C. after D. until
[答案] D
[解析] 講故事的人應(yīng)該始終抓住聽眾的好奇心，本題應(yīng)選用表示到為止(跟主句里肯定形式的表延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用)的until 表示這一時(shí)間關(guān)系。
[考題10] I dont really work here; I ____ until the new secretary arrives.
A. just help out B. have just helped out
C. am just helping out D. will just help out
[答案] C
[解析] I dont really work here表明說(shuō)話人只是臨時(shí)前來(lái)幫忙，until the new secretary arrives表明說(shuō)話人，工作到新秘書就任為止，本題應(yīng)選用表示到為止(跟主句里肯定形式的表延續(xù)性動(dòng)作的謂語(yǔ)動(dòng)詞連用)的until表示這一時(shí)間關(guān)系。
4. since引導(dǎo)的時(shí)間狀語(yǔ)從句分析：
since引導(dǎo)的時(shí)間狀語(yǔ)從句表示自從以來(lái)，其用法主要有兩種：
(1) 現(xiàn)在完成時(shí)的主句+since引導(dǎo)的一般過(guò)去時(shí)態(tài)的時(shí)間狀語(yǔ)從句。例如：He hasnt been home since he graduated. 他畢業(yè)后沒回過(guò)家。// They have been friends ever since they were in grade school. 他們從小學(xué)起就一直是好朋友。// What have you been doing since I last saw you? 自我上次和你見面以后，你在做什么?
(2) It be(主句中謂語(yǔ)用一般式和用完成式區(qū)別不大，后者更具強(qiáng)調(diào)意味)+表示一段時(shí)間的詞匯+since引導(dǎo)的時(shí)間狀語(yǔ)從句。例如：It is two years since I became a postgraduate student. 我成為研究生已經(jīng)有2年了。It was three years since we had been there. 我們?cè)谀莾阂汛袅巳辍?/p>
注意：since做介詞時(shí)也表示自從以來(lái)，其具體用法有兩種情況：
(1) since+表示過(guò)去某個(gè)時(shí)間點(diǎn)的詞匯(如具體的年、月、日期、鐘點(diǎn))。
例如：They have been friends since childhood. 他們從幼時(shí)起一直是好朋友。Shes been skiing since childhood. 她從幼時(shí)起就開始滑雪。I have been there many times since the war. 自那次戰(zhàn)爭(zhēng)以來(lái)，我曾去該地多次。
(2) since+表示一段時(shí)間的詞匯+ago。
例如：I have been here since five months ago. 五個(gè)月以來(lái)我一直在這里。
[考題11] They ____ friends since they met in Shanghai.
A. have made B. have become C. have been D. have turned
[答案] C
[解析] 題干中的since表示自從以來(lái)，主句中的謂語(yǔ)動(dòng)詞應(yīng)該表示從他們?cè)谏虾Ｏ嘤鲋两竦某掷m(xù)性的動(dòng)作，因此下劃線處應(yīng)填入可以表示持續(xù)性狀態(tài)的have been(其他選項(xiàng)中的made、become、turned所表示的動(dòng)作都不能延續(xù)，意味著結(jié)果)。
[考題12] What was the party like?
Wonderful. Its been 2 years ____ I enjoyed myself so much.
A. after B. before C. when D. since
[答案] D
[解析] since表示自從以來(lái)。
