中考英语《状语从句》课件 外研版..ppt

状语从句 A.时间状语从句： 1. I’ll tell him about it when he comes back. 2. He didn’t go to bed last night until his father came back. 3. Please call me as soon as you get there. 4. He run off before I could stop him. (我还没来得及拦住他，他就逃跑了，before后常含情态动词) 常由when, while, as, since, after, before, until/till, as soon as等连词引导。 **注意事项： 1．主句是将来时(或含情态动词的现在时，或主句是祈使句)，从句常用现在时来代替将来时(即“主将从现”)。 1. After she finishes her homework, she can watch TV for an hour. 2. He won’t leave the school until he finds the library book. 3. Don’t get off the bus until it stops. 2．在由until / till 引导的时间状语从句中，当主句的谓语动词表达否定义时，谓语动词是瞬间性动词。 He didn’t come back until it was too late. 当主句的谓语动词表达肯定义时，谓语动词是延续性动词。 例：He waited until it was too late. 3．since引导的从句，主句常用现在完成时，从句则用一般过去时。 1. He has visited a lot of places since he came to China. 2. It is many years since World War Two was over. 4．as, when与while  as : A.“当------时候”，(=when) As she was walking in the park, she heard a cry for help. B. “一边------，一边-----”表同步发生或进行。 The girls danced as they sang. They talked as they walked. when “当------时候”，引导时间状语从句时，即可指“时间点”也可指“时间段”，相应的从句中谓语动词须为“终止性的”或“持续性的”。 I was watching TV when he came into my house. (终止性动词) I fell down on the ice when I was skating quickly. (持续性动词) (when=while) 注意： when 可用于主句动作正在进行的过程中(进行时)，从句动作突然发生(一般时)。 I was walking in the park when it began to rain, I got wet soon.(=just at that moment) while “当------时候”，只指“时间段”，不指“时间点”，( while= dring the time---)表示主句的行为在从句行为过程之中发生，所以从句中只能用持续性动词或状态动词，并且持续性动词常用进行时态。 Someone knocked at the door while I was cooking. (while = when ) I read the newspaper while I waited for the bus 提示：用while的句子同样都可以用when；而用when的句子不一定都可以用while. B.条件状语从句：常由连词if, unless(如果不=if not), so long as(只要),so far as等引导。 We’ll go to the park if it doesn’t rain. = We’ll go to the park unless it rains. 2. We can surely overcome these difficulties so long as we are closely united. 3. If you don’t hurry, you’ll be late. =H