1、一、 before用作连词 (3) 1 before用作连词时,意思是“在之前;还没来得及 就”。例如: Before I could say a word, she had rushed out of the room. 不等我说一句话,她就冲出了房间。 Dont count your chickens before they are hatched. 不要高兴得过早。,before用法,2 用于It + be + 时间段 + before.句型中,意思是“在之后才”。例如: It will be five years before I come back. 我五年后才能回来。 It was
2、 not long before the enemy was driven out of their country. 不久之后,敌人就被赶走了。 如果主句中用否定式,则表示“不多久就”。 It wont be long before they understand each other. 他们不久就会互相了解的。,3 还有“趁(还没有)”之意。 例如: They are thinking of buying the house before the prices go up. 他们正在考虑趁房价未涨时把房子买下来。 Do it before you forget it. 趁早动手,以免忘了。
3、,二、before用作介词 before用作介词时, 可以指时间“earlier than在之前”,也可以指位置“in front of在之前”。例如:Several weeks had gone by before I realized it.在我意识到之前几周已经过去了。The scientists had tried out many kinds of chemicals before thy found the right one . 再发现最合适的化学物质之前,科学家们已经试过很多种了。He was brought before the judge. 他被带到法官面前。,三、befo
4、re用作副词 before用作副词时,意思是“at an earlier time / in the past以前”。例如: Ive seen the film Titanic before. 我以前看过泰坦尼克这部电影。 I have never seen such beautiful flowers before. 我以前从未见过如此美丽的鲜花。,before long “很快,不久” 各种时态long before “很久以前” 一般用在过去时或过去完成时 例如: Before long, he went to America. 不久他就去了美国。 I hope to see you b
5、efore long. 我希望不久后再见到你。 She said she had read the novel long before. 她说她很久以前就读过这部小说。 That happened long before. 那件事发生在很久以前。,before long与long before的区别 do you know?,一.用作介词, 意思是“从以来, 自从”, 常与完成时连用。 I havent written home since Christmas 自圣诞节以来, 我未曾写信回家。二.用作副词,意思是“从那时以后(一直到现在)”, “其后(到现在之间)”; ever since从那
6、以后一直 (更加强调since的用法)。,Since 的用法,Things have not changed very much since. 从那时起, 情况并没有太大的改变。 His first book was a great success and he has been famous as a writer ever since. 他的第一本书非常畅销, 从那时起他就成了一位名作家。 He got a job with the firm in 1970 and has worked there ever since. 他从1970年开始在那家公司任职, 之后就一直在那里工作。,三.用
7、作连词 1. 引导原因状语从句,相当于now that,意思是“因为,既然, 鉴于”。 Since the rain has stopped, lets go for a walk. 既然雨停了, 我们出去散散步吧。 Since we are young, we shouldnt be too afraid of making mistakes.因为我们还年轻, 所以不应该太害怕犯错误。,注意:since表示原因时, 语气比because弱, 表示的原因是对方已知的,或是句中不很重要的部分, 是附带的原因, 因此引导的从句不是信息的焦点, 不能回答why的提问, 也不能用在强调句型中作为被强调
8、的内容。(since引导的从句往往放在主句之前。),2. 引导时间状语从句,此用法较复杂。 (1) 若since引导的状语从句的谓语动词是终止性动词(如go,come,leave, start, begin等)的过去时, 则从句表示的时间是“从该动作开始的那一时刻起”。 He has studied very hard since he came to our school. 自从来到我们学校, 他学习就非常努力。 Great changes have taken place in our school since you left. 自从你离开这里, 我们学校发生了很大的变化。,(2) 若s
9、ince引导的状语从句的谓语动词是持续性动词或表示状态的静态动词(如live, stay, study, learn, smoke, be等)的过去时, 则从句表示的时间是“从该动作或状态的完成或结束时算起”。如: I havent heard from him since he lived here. 这句话应译为:从他不住这儿起, 我一直没有收到他的信。 I havent eaten snakes since I was a student at school. was表示状态,因此该句可理解为:I havent eaten snakes since I left school. 自从我毕
10、业后就一直没吃过蛇。,试翻译比较: He has written to me frequently since I was ill. He has written to me frequently since I fell ill.,(3) 若since引导的状语从句的谓语为持续性动词或静态动词的现在完成时, 则表示动作和状态延续到现在(说话时刻), 其表示的时间的起点应从动作发生之时算起。如: He has written to me frequently since I have been ill. have been ill表示状态的持续性(理解时注意与区别), 时间的起点应从:“开始生
11、病”时算起。因此此句可理解为:“自从我生病以来, 他经常给我写信。”,试比较翻译: Ive written her 20 letters since I have been here. (从开始算起) Ive written her 20 letters since I was here. (从结束算起),(4) It is + 段时间 + since. / It has been + 段时间 + since.表示“从起已有多长时间了”。 用法注意:since从句中常用一般过去时,若从句中是持续性动词的一般过去时, 则表示该动作结束有多长时间了。It is three years since
12、he smoked. 他不吸烟已有3年了。 注意:在这种结构中, since引导的从句绝对不能用否定式的谓语动词来表示否定意义 翻译 : 他好久没学汉语了。,误:It is a long time since be didnt study Chinese. 正:Its a long time since he studied Chinese. (studied为持续性动词, 应从其动作结束时算起),请看有关高考题(答案为DDBCDC): 1. That was really a splendid evening. Its years _ I enjoyed myself so much. (安
13、徽卷) A. when B. that C. before D. since 2. It was some time _we realized the truth. (山东卷) A. when B. until C. since D. before 3. Did Jack come back early last night? Yes. It was not yet eight oclock _he arrived home. (福建卷) A. before B. when C. that D. until,4. Scientists say it may be five or six yea
14、rs _it is possible to test this medicine on human patients. (福建卷) A. since B. after C. before D. when 5. It was evening we reached the little town of Winchester. (天津卷) A. that B. until C. since D. before 6. It _ long before we _ the result of the experiment. (上海春) A. will not be; will know B. is; wi
15、ll know C. will not be; know D. is; know,小结,(2004天津)It was evening _ we reached the little town of Winchester. A that B. until C. since D. before 2.(2004全国)Several weeks had gone by _ realized the painting was missing. A. as B. before C. since D. when 3.(2005广东)The America Civil War lasted four year
16、s _ the North won in the end. A. after B. before C. when D. then,4.(2005山东)It was some time _ we realized the truth. A. when B. until C. Since D. before 5.(2006四川)-Why didnt you tell him about the meeting? -He rushed out of the classroom _ I could say a word. A. before B. until C. when D. after 6.(2006福建)-How long do you think it will be _ china sends a manned spaceship to the moon? -Perhaps two or three years. A when B. until C. that D. before,参考答案:DBBDAD,