时间和原因状语从句PPT课件

1、状语从句,状语从句主要用来修饰主句或主句的谓语。一般可分为八大类, 分别表示时间、地点、原因、目的、结果、条件、让步、比较。尽管种类较多, 但由于状语从句与汉语结构和用法相似, 所以理解和掌握它并不难。状语从句的关键是要掌握引导不同状语从句的常用连接词和特殊的连接词即考点。,状语从句简介,.,3,.,4,在时间状语从句中，通常要用动词的一般现在时态表示将来时，用一般过去时表示过去将来式。 时间状语从句常用连词有： when, as, while, whenever, after, before, till (until), since, once, as soon as (或the momen

2、t ), by the time, no sooner than, hardly (scarcely) when, every time等引导。,一、时间状语从句,.,5,(1) when 意为“当时”，引导的时间状语从句表示主句的动作和从句的动作同时或先后发生。如：,I feel very happy when you come to see me. 你(们)来看我时，我感到很高兴。 When you are crossing the street, you must be careful. 你( 们)过街道时，一定要小心。,1.考查when, while, as引导，表示“当时候”。,一、

3、时间状语从句,.,6,when 引导的时间状语从句中，可以用延续性动词，也可以用短暂性动词。如：,Someone knocked at the door when I was sleeping. 当我正在睡觉时，有人敲门。(延续性动词),I will visit my good friend when I arrive. 当我到达时，我将去看望我的好友。(短暂性动词),一、时间状语从句,.,7,注意：when 也可以作并列连词，表示一个动作正在进行的时候，突然间发生了另外一件事。如：,I was fishing by the river, when someone called for hel

4、p. 我正在河边钓鱼，就在那时有人求救。,We were working in the chemistry lab, when the lights went out. 我们正在化学实验室工作，突然灯都熄灭了。,一、时间状语从句,.,8,.,9,(2)while 意为“当时”“在期间”，引导的时间状语从句表示主从句的动作在同一时期发生，常用延续性动词或表示状态的词。如：,They rushed in while we were discussing problems. 当我们正在讨论问题时，他们冲了进来。 Father was cleaning the car while I was play

5、ing computer games. 当我正在玩电脑游戏时，爸爸正在清洗汽车。,一、时间状语从句,.,10,(3) as 意为“当时”“一边一边”“随着”， 主从句动作同时发生。如：,As they walked, they talked happily. 他们一边走，一边高兴地交谈着。,一、时间状语从句,注意：while 也可以作并列连词，表转折的关系， 相当于but，译为“然而”。如：,I like listening to music, while my brother likes doing sports. 我喜欢听音乐，而我的兄弟爱好运动。,三者均可表示“当的时候”, 如果主句表示

6、是短暂性动作, 而从句表示的是一段时间,（同时发生） 三者可通用。 1.It was snowing _ we got to the airport 当我们到达机场时, 天正下着雪。 2. He sang _ he went along. 他边走边唱. 3. _the day went on, the weather got hotter. 随着日子天天过去，天气越来越热。 4._ he reached home, he had a little rest. 回到家后, 他休息了一会儿。 5._l was walking down the street，I saw some policemen

7、 6._they heard the news，they were surprised 7._the child was playing with his toys, his parents were watching TV.,疑点解释,When/While/As,While,When,when,as,As,When,.,12,答案A解析 答语中when引导了一个时间状语从句，主句用了一般将来时态，所以从句用一般现在时态，可见正确答案在A与B之中。既然答语用了时间状语来回答，可见问句询问的也一定是时间，从而确定正确答案为A。,【考例】Mum,_ shall we have lunch? We

8、will have it when your dad_. 连云港 A when；returns B where returns Cwhere；will return Dwhen；will return,.,13,【考例1】一Hurry up. The bus is coming Oh, no. We mustnt cross the street _the traffic lights are green福州 Aafter B. since C. while Duntil,答案D。解析本题应从句意人手。until常用于否定句中，构成notuntil结构，意为“直到才”，该句意为“直到交通灯变绿

9、，我们才能穿过马路”。,.,14,二、原因状语从句 原因状语从句，常用的引导连词有 because (因为), as (由于)和 since (既然)。 (1)because: 语气最强，回答why时用because，所表示的是直接理由，因果关系不能同so连用。 because 的从句常放在主句之后 Why did you go？你为何去？ I went because Tom told me to go. 那是因为汤姆叫我去。,.,15,二、原因状语从句 (2) since: “既然.” 表对方已知的事实或理由，常放在句首。 Since you feel ill, youd better n

10、ot go to work. 既然你感觉不舒服，你最好不要去上班了。 (3) as: “由于.” 语气较弱，较口语化，表明显的原因或已知的事实，常放在句首。 As it was raining hard, we had to be indoors. 由于雨太大，我们只好待在家里。,.,16,【考例】 Mark isnt coming to the concert _ he has got too much work to do. Aso Buntil Calthough Dbecause,答案D解析so“因此”；until“直到”；although“虽然”；because“因为”。“太多工作要

11、做”是“没有来音乐会”的原因。,.,17,结果状语从句，常由“so.that.” “such.that.” (如此以致)引导。如：,He is _short _ he cant reach the apple. 他太矮了，够不到那个苹果。 It is _ a heavy box _ I cant move it. 这是个很重的箱子，我搬不动它。,三、结果状语从句,.,18,【考例】The camera is expensive I cant afford it. (本溪) so, that B. such, that C. so, as to D. enough, that,答案 A 解析 依

12、据题意：这照相机太贵以致我买不起。expensive为形容词,sothat句中要用形容词或副词；suchthat要用形容词修饰名词。其他两项不能引起从句。故选A。,.,19,引导目的状语从句的从属连词有 so that , in order that (为了，以便)；in case(以防，以免)，lest(免得，以防)，for fear that(以免，惟恐)等。从句中一般含有can , could, may, might ,will, would等情态动词。如：,四、目的状语从句,.,20,【考例】More and more people in Beijing are learning En

13、glish _they can better serve（服务） the 2008 Olympic Games Im sure they will宜昌 Abecause of B so that Ceven though Das if,答案B解析 本题也应从句意人手。越来越多的人学习英语，“为的是”能更多更好地为奥运服务。so that引导一个目的状语从句。,.,21,用来引导让步状语从句的从属连词有：though，although，even ifthough， while(虽然、尽管)，for all (that)(尽管)whetheror(不论不管还是)以及“疑问词+ever（whatev

14、er，wherever，whoever，however，）”和 “no matter +疑问词”等。 Though he was very tired, he didnt stop working. 尽 管 他 很累，他没有停止工作。,五、让步状语从句,.,22,五.让步状语从句 though 和although的区别,作连词引导让步状语从句时，意思大致相同，一般可互换，但although语气较重，通常放在句首并用于正式场合。 如： Id quite like to go out, although/ though it is a bit late. 我很想外出，虽然为时稍晚。,.,23,五.

15、让步状语从句 2. though 可用于even though, as though 等固定结构，although则不能。 如：Even though I fail, Ill keep on trying. 我纵然失败，仍会继续尝试下去。 You look as though you know each other. 看起来你们好像彼此认识。,.,24,【考例1】Shall we go on working? Yes , I prefer to have a rest .（南昌） Awhen Bif C. because Dthough,答案 D解析 依据上句：我们继续工作吗？是的，尽管我想休

16、息会。,【考例2】Edison never gave up, he failed many times. (四川) AandBthoughCor,答案 B解析 依据题意：即使爱迪生失败多次，他也决不放弃。though用来引导让步状语从句。故选B。,.,25,引导条件状语从句的从属连词有if , unless(=if not如果不，除非)，as/so long as ,while(=as long as 只要)，supposing(that),provided/providing(that),in case(假使)，on condition that(在的条件下)等。我们主要看一下由 if 引导

17、的条件状语从句。,六、条件状语从句,.,26,六、条件状语从句 if 意为“如果”，引导一般条件状语从句时，主句用将来时，从句用一般现在时。如： If it doesnt rain tomorrow, we will go there by bike. 如果明天不下雨，我们就骑自行车去那里。 If I get there early, I can see the doctor quickly.如果我早早地到那里，我就可以快点看病。,.,27,【考例1】_you go to bed earlier, you wont feel tired in the mornings沈阳市 A. Unless

18、 B. Because C. If D. When,答案C 解析考查if引导的条件状语从句。“假如你早一点上床睡觉，那么你在上午就不会感到累。”,.,28,【考例2】You wont pass your exams _ you work harder. 广东 A. when B. if C. unless D. after,答案C解析when，after一引导的是时间状语从句，不合题意；if，unless引导的是条件状语从句，If不合句意，“除非你更加努力地学习，否则，你不会通过考试”。故用unless。,.,29,比较状语从句常用than或asas引导。than表示两者的比较，asas表示程

19、度相同。如： Im taller than Tom is. 我比Tom高。 He runs as fast as I do. 他和我跑得一样快。,七、比较状语从句,.,30,【考例】The days are_ in our country. Aas warm asBas warmer as Cwarm than D. so warm as,答案 A。,【考点1】区分when, if引导宾语从句和状语从句的不同: when引导时间状语从句意为“当时候”, 引导宾语从句意为“什么时候”; if引导条件状语从句意为“如果”, 引导宾语从句意为“是否”。如:,八. 对状语从句和宾语从句、简单句、并列句

20、的混合考查,1. Mike wants to know if _ a picnic tomorrow Yes. But if it _, well visit the museum instead A. you have; will rain B. you will have; will rain C. you will have; rains D. will you have; rains,C,2. Do you know when he _ back tomorrow？ Sorry, I dont. When he _ back, Ill tell you A. comes; comes B. comes; will come C. will come; comes D. will come; will come,C,1) It _ ten years since they _ to France. A. as; covered B. was; have moved C. is; have moved D. is; moved 2) He _ wait until the rain _ A. wont; will stop B. wont; stop C. will; stops D. will; will stop,选择题,D,C,3) He wi