初中英语语法归纳：状语从句

初中英语语法归纳：状语从句

‎ ‎ 初中英语语法归纳：状语从句 ‎ 状语从句是用来修饰主句中的动词，副词和形容词的从句。根据其含义状语从句可分为时间状语从句，地点状语从句，条件状语从句， 原因状语从句，结果状语从句，比较状语从句，目的状语从句，让步状语从句。‎ ‎　　1. 时间状语从句 ‎　　(1)时间状语从句常用when, as, while, before, after, since, till, until, as soon as等连词来引导。例如：‎ ‎　　It was raining hard when got to school yesterday.‎ ‎　　While he was doing his homework, the telephone rang.‎ ‎　　As he walked along the lake, he sang happily.‎ ‎　　He had learned a little Chinese before he came to China.‎ ‎　　After he finished middle school, he went to work in a factory.‎ ‎　　(2)在时间状语从句里，通常不用将来时态，用现在时态表示将来的动作或状态。例如：‎ ‎　　I’ll ring you up as soon as I get to New York.‎ ‎　　I will tell him everything when he comes back.‎ ‎　　He won’t believe it until he sees it with his own eyes.‎ ‎　　(3)在带有till或until引导的时间状语从句的主从复合句里，如果主句用肯定式，其含义是“一直到……时”，谓语动词只能用延续性动词。如果主句用否定式，其含义是“直到……才……”, “在……以前不……”, 谓语动词可用瞬间动词。例如：‎ ‎　　The young man read till the light went out.‎ ‎　　Let’s wait until the rain stops.‎ ‎　　We won’t start until Bob comes.‎ ‎　　Don’t get off until the bus stops.‎ ‎2. 条件状语从句 ‎　　(1)条件状语从句通常由if, unless引导。例如：‎ ‎　　What shall we do if it snows tomorrow?‎ ‎　　Don’t leave the building unless I tell you to.‎ ‎　　(2)在条件状语从句里，谓语动词通常用现在时态表示将来的动作或状态。例如：‎ ‎　　I’ll help you with your English if am free tomorrow.‎ ‎　　He won’t be late unless he is ill.‎ ‎　　(3)“祈使句 + and (or)+ 陈述句” 在意思上相当于一个带有条件状语从句的复合句。例如：‎ ‎　　Hurry up, or you’ll be late.‎ ‎　　=If you don’t hurry up, you’ll be late.‎ ‎　　Study hard and you will pass the exam.‎ ‎　　=If you study hard, you will pass the exam.‎ ‎3. 原因状语从句 ‎　　(1)原因状语从句通常由because, since, as引导。例如：‎ ‎　　He didn’t come to school because he was ill.‎ ‎　　As it is raining, we shall not go the zoo.‎ ‎　　Since you can’t answer the question, I’ll ask someone else.‎ ‎　　(2)because表示直接原因，语气最强。Because引导的原因状语从句多放在主句之后。回答由why提出的问题，只能用because。As和since语气较弱，一般用来表示明显的原因。由as和since引导的原因状语从居多放在句首。例如：‎ ‎　　------Why aren’t going there?‎ ‎　　------Because I don’t want to.‎ ‎　　As he has no car, he can’t get there easily.‎ ‎　　Since we have no money, we can’t buy it.‎ ‎　　(3)because和so不能同用在一个句子里。‎