状语从句知识概况.docx

状语从句状语从句包括:时间、地点、条件、原因、目的、结果、让步、方式、比较状语从句。一. 时间状语从句主要连词：when、while（当…时候）、as（当…时候）、as soon as（一......就......）、before、after、since、until/till等。When:特定的时间When I was 20,I started working.While：两件事同时做While I was sleeping, he was studying.As:两个动作同时发生或几乎同时发生；某事发生的过程中另一件事发生。As I earn more money, I spend more.Since:自从She has been living a hard life since her husband died.Until：动作持续到某个时候之前Will this food keep until tomorrow?By the time:动作在一个时间点之前完成By the time he arrived at the airport, the plane had taken off.注：①谓语是延续性动词时，when和while、as可以互换，都是“当…时候”When/While/As we were dancing, a stranger came in.When/While/As I was taking a bath, the telephone rang.②When, While和As的用法区别：when的谓语动词可以延续性和非延续性，而while只能延续性。When you come in, I was talking with a few boys.While we were waiting for the bus, it was raining heavily.While I was away last summer, my dog was taken good care of.When I lived in that small village，I often went to play in the field.When the film ended，all the people began to go out of the cinema. 2) while和as动作同时发生，when的从句动作是主句动作之前或后，或同事发生。 They rushed in while/as we were discussing problems. When he had finished his homework, he took a short rest. When I got to the airport ,the guests had left. 3)while是两个延续性动作同时发生又有对比意义，主从句时态一致。 While she was making a phone call, I was writing a letter. Andy was sleeping while Mary was reading a magazine. 4)as为“一边…一边…”动作同时发生或几乎同时发生；某事发生过程中另外一件事发生。 As you grow older, you will know better and better about yourself. As he was reading, he was shaking his head. 【注意1】时间状语从句要符合“主将从现”的原则：即主句用一般将来时，从句用一般现在时。例如：I will call you as soon as I arrive in Beijing.I will give you a call when I arrive at London.【注意2】since主句：现在完成时或一般现在时，从句：一般过去时。Since I came to Beijing, I have lived here.I have lived in England since I was three.It is two years since I became a college student.***“ It is/has been + 时间段 + since从句”———自从…以来有（多久）。Since不可以用在否定句。It is/has been 5 years since we last met.It is/has been a long time since Mary was ill.【注意3