时间状语从句通常修饰整个主句或主句的谓语动词.ppt

时间状语从句通常修饰整个主句或主句的谓语动词，表示时间。引导时间状语从句的连词或词组通常有：,1. when, whenever,when作为连接副词，意思是“当时”、“在时”。when从句是最常见的时间状语从句，它通常表示从句的动作和主句的动作同时发生或先于主句发生。Whenever是的强调形式，意思是“无论什么时候”。,例如： When they were still laughing, the teacher came in. It was already dark when we got home. When you think you know nothing, then you begin to know something.,When引导的时间状语从句有时也可以表示从句的动作发生在主句的动作之后。例如： When he arrived at the station, the train had already left. When we bought the house, it had been empty for five years.,When引导的时间状语从句一般不能和表示将来的时间连用，通常用现在一般时和现在进行时表示将来。例如：,I will discuss this with you when we meet. He will go when he has his dinner. I hope you will think of me for a moment when I am taking my driving test.,2. while 引导得从句动作与主句的动作同时发生, 从句的时间范围多大于主句的时间范围。 I kept watch while they slept. Work while you work, play while you play.,When引导的从句表示的时间可以是某一瞬间或某一点，而while从句不能指时间的某一点。 The plane had just taken off when we arrived at the airport. Please let me know while he comes.,while除表示时间之外, 还可以用作并列连词, 连接一个表示对比的并列句,意思是“而”、“启事”、“反之”等，相当于whereas。,He likes playing basketball while I like playing football. Jane was dressed in brown while Mary was dressed in blue.,3. as as引导的时间状语从句的动作与主句的动作是同时发生的。 As he was making his experiments, he observed this physical phenomenon.,As 引导的状语从句经常用进行体，表示主句动作是在从句动作进行的过程中发生的。 The thief was arrested as he was leaving the bank.,4. when, while, as三者之间的区别： when表示的时间范围比较宽，从句的动作可以与主句的动作同时发生，也可以先于主句或后于主句发生，且语气较强。While从句多表示一个过程，它表示的动作所持续的时间比as和when长。As表示两个动作同时进行，着重“同时”。,5. before 主句用将来时，从句要用现在一般时。如主句用一般过去时或过去完成时，从句常用一般过去时。Before引导的从句不能用否定式谓语。英语不能说“before he did not come”。 Later someone told me that the story appeared in a magazine shortly before he died. She will come to see you before she leaves Shanghai.,6. after 主句是现在一般时和过去一般时，从句常用现在一般时或现在完成时和过去一般时或过去完成时。主句的动作表示的是将来的时间，从句要用现在一般时。 What do you plan to do after you have finished your homework? After we had listened to the report, we held a discussion on it. I shall arrive after you leave.,7. until / till 在肯定句中，till比until用的普遍。Until多用于正式文体，放在句首较多，语气较重。如果主句动词表示的是将来的时间，从句要用现在一般时。在肯定句中，主句必须用延续性动词。 We shall wait until you come back. Until we know the facts, we can do nothing further.,在否定句中，until表示“直到才”，和before同义。 People had no idea of radioactivity until Madame Curie discovered radium.,有时为了加强语气，可以将主句中的否定词放在until之前，主句的主语和谓语同时采取倒装语序。 Not until her daughter fell asleep did the mother leave the room. It was not until he was actually dying that he said” I can work no more”. It was not, however, until the steam engine was invented that coal-mining became an important industry.,8. since since引导的从句，通常用过去一般时，主句通常用现在完成时。 You havent changed much since we met last year. Since I left college, I have not seen him.,带有since引导的从句，主句通常要用现在完成时。但是当主句的主语是指时间的代词，主句的概念已经包含了从过去到现在的持续时间，主句也可以用现在一般时或过去一般时。 It is fifty years since we saw you last.,Since还可以与ever连用，构成ever since。意思是“自从以后一直”。 They have studied English ever since they entered university.,9. as soon as, once, directly, immediately, instantly, the moment, the instant, the minute as soon as和once是常用的从属连词，其余的是由副词或词组转化而来的连词。As soon as和once的细微区别是：前者强调时间的紧接，后者带有条件意味。,As soon as you finish your work, let me know. Once you begin, you must continue.,Instantly, immediately, directly这几个词都是副词演变而来的从属连词，他们的细微区别是：instantly语气最强，动作最急; immediately语气比instantly稍弱; directly又次之, 动作不是那样急迫。,Instantly I arrived there I telephoned him. I got up to open the door immediately the bell rang. Well go to school directly we have finished our breakfast.,The moment, the instant, the minute的意思和用法一样. 为了加强语气, 还可以在moment前面加上very。 Current will start again the moment the break of the circuit is mended. We thrilled with joy the very minute we set foot on the soil of our motherland.,10. no soonerthan, hardly when, scarcely when, barely when 这四个从属连词的意思都是“一就”, 表示从句的动作紧接着主句的动作发生。该句型的特点是：从句多用过去一般时, 主句用过去完成时。,We had no sooner sat down than they left. He had hardly left the home when it began to rain. They had hardly got to the factory when they began to work. I had scarcely stepped out of the house when I heard a shot within. She had scarcely done it when she regretted it.,有时这个句型的从句可以用现在一般时, 主句用现在完成时, 但它指的是一种经常性的动作。 The day has scarcely broken when he gets up.,该句型中的when有时还可以换成before。 He had hardly signaled to turn before the other car turned in front of him.,当no sooner, hardly, scarcely, barely放在句首时, 主句的主语和谓语要倒装。 No sooner had we reached the top of the mountain than we all sat down to rest. Hardly had the girl seen her mother when she ran across the grass.,11.every time, each time, by the tim