.重点语法 时间状语从句 1。引导词：

（1） when, while , as 当……时候. when 后可跟短暂性动词也可跟延续性动词；while 后跟延续性动词；as 多用于口语，强调同一时间，或一前一后。 The students were talking in the classroom when the teacher came in. = While the students were talking in the classroom , the teacher came in. 学生在教室里谈话时，老师进来了。 Mother always sings as she cooks dinner for us. 妈妈总是边给我们做饭边唱歌。

（2）not … until 直到……才，主句谓语动词常用短暂性动词。 I won't leave here until the rain stops. He didn't sleep until his mother came back home. (3) after 在……之后，before 在……之前，as soon as 一……就 I went to sleep after I finished my homework..= I finished my homework before I went to sleep. As soon as the bell rings , the students will go into the classroom. 2. 时态

（1）当主句为一般过去时时，从句常用过去的某种时态。 While I was doing my homework , the telephone rang. (2)当主句的时态为一般将来时， 从句用一般现在时。 I will call you as soon as I get to Beijing. 本topic出现的句子有： 1.While you were enjoying your trip, I was busy preparing for my exams. 2.He didn't raise his head until someone called his name. 3.While the crowd was pushing him in different directions, someone stepped on his toes. .4. As soon as the three boys saw each other, they all jumped up happily. 5.After they rode their bikes for two and a half hours, Kangkanf , Michael and Darren arrived at the Ming Tombs. 6.As they were exploring happily, the crowd became larger and larger. Topic3 Bicycles are popular with people 重点语法 条件状语从句 1.条件状语从句由if（如果），unless（除非）等 引导的，谓语动词常用一般现在时表示将来，主句用一般将来时。 主句 if从句 Will (must, should, may) 一般现在时 如：I won't go if he doesn't go . We will pass the exam if we study hard. We won't pass the exam unless we study hard.. 2. 祈使句 and/or 引导的结果句，祈使句在意义上相当于条件状语从句。 如：Hurry up, or you'll be late.= If you don't hurry up, you'll be late.=You'll be late unless you hurry up. Study hard, and you will pass the exam.= If you study hard, you will pass the exam.