英语九年级【知识精讲】13.句法(26)条件状语从句 课件

这是一份英语九年级【知识精讲】13.句法(26)条件状语从句 课件，共15页。PPT课件主要包含了条件状语从句，时间状语从句，状语从句，原因状语从句，目的状语从句，结果状语从句，地点状语从句，宾语从句，让步状语从句，定语从句等内容，欢迎下载使用。

在某种条件下，一件事情可能发生。条件是指某一件事情发生之后，另一件事情才能发生，引导词常表示“假如，只要，如果”等。
条件状语从句中，主从句的时态要遵循“主将从现”的原则。
条件状语从句的引导词：if，unless，as (s) lng as
1. 主将从现原则：主句用一般将来时，if引导的从句用一般现在时表将来。If yu ask him, he will help yu. If yu fail in the exam, yu will let him dwn. 2. if引导虚拟条件句，表示不可实现的条件或不存在的条件，从句中多用一般过去时或过去完成时，be动词只能用were。 If I were yu, I wuld invite him t the party. What wuld happen if there were n water?
3. 含有if从句的复合句中，主句中的will可用情态动词来代替。If there is n water, we can’t live.4. if从句的复合句中，主句也可以用祈使句。Please stay at hme if it blws heavily tmrrw.5. 含有介词with和withut的介词短语。If there is n water, fish can’t live.=Fish can’t live withut water.
6. 同义句转换用祈使句+“，”+and/r+一般将来时If yu wrk hard, yu’ll pass the exam easily.=Wrk hard, and yu’ll pass the exam easily.If yu dn’t hurry up, yu’ll miss the train.=Hurry up, r yu’ll miss the train.
unless “除非，若不”
unless可与互换Yu will fail t arrive there in time unless yu start earlier. Unless it rains, the game will be played. unless = if… nt 主将从现If yu dn’t g, I wn’t g.=Unless yu g, I wn’t g.
as lng as (=s lng as) “只要”
As lng as yu prmise t cme, I’ll wait fr yu until yu cme. 只要你答应，我就等你来。S lng as yu're happy, I will be happy. 只要你高兴，我就高兴。
在条件状语从句中，用一般现在时代替一般将来时，一般过去时代替过去将来时。If it rains tmrrw, we will nt g t the park.He said he wuld cme t see yu if he had time.
按要求完成下列各题。The fish will g bad, s yu'd better put it in the fridge．(改为同义句)The fish will g bad ______ yu ______ put it in the fridge．
按要求完成下列各题。The fish will g bad, s yu'd better put it in the fridge．(改为同义句)The fish will g bad ______ yu ______ put it in the fridge．答案：if; dn't
单项选择。—Let’s g fishing if it ______ this weekend. —But nbdy knws if it ______.A. is fine; will rainB. will be fine; rainsC. will be fine; will rainD. is fine; rains
单项选择。—Let’s g fishing if it ______ this weekend. —But nbdy knws if it ______.A. is fine; will rainB. will be fine; rainsC. will be fine; will rainD. is fine; rains答案：A