unit3 When和while引导的时间状语从句

Unit3WhatwereyoudoingwhentheUFOarrived?,过去进行时的概念及构成,构成：主语+was/were+doingsth+时间状语,概念：表示过去某一时刻或某段时间正在进行的动作,指示词：then、atthattime、once等连用，或者用另一动作来表示过去的时间。,when和while的用法与区别,1、延续性动词与非延续性动词,延续性动词指动作可以延续一段时间，而不是瞬间结束。,如：workstudydrinkeat等,非延续性动词指动作极为短暂，瞬间结束。,如：startbeginhitjumpknock等,When与while引导的时间状语从句,When表示”当时候”。从句中既可以用延续性动词，又可以用非延续性动词，这些动词既可以表示动作，又可以表示状态。从句中的动作既可和主句动作同时发生，又可在主句动作之前或之后发生。,如：MarywashavingdinnerwhenIsawher.Theboywasstillsleepingwhenhismothergothomeyesterdayevening.,When与while引导的时间状语从句,While表示“在时候”、“在期间”。它强调主句的动作与从句的动作同时发生，或主句的动作发生在从句的动作过程中。While从句必须是表示动作或状态的延续性动词。如：TheweatherwasfinewhilewewereinBeijing.ShecalledwhileIwasout.如果主句的动作在从句的动作过程中发生，从句常用进行时，如：WhilewewereswimmingsomeonestoleourclothesDonttalksolouldwhileothersareworking.,Summary,1.When可指时间点，又可指时间段，从句中可用延续性动词，也可用非延续性动词。2.While总是指一个时间段，从句中必须用延续性动词。3.统一时态：主句过去式，从句也是过去式。,Exercises:fillwith“while”or“when”,Maywastalkingonthephone,hersisterwalkedinRitaboughthernewdog,itwaswearingalittlecoat.IsawCarlos,hewassinginglouldly.Iwasdancing,hewassinginglouldly.LindafinallysawDavid,hewasjumpingwithadog.Iwascleaningmyroomthefirebrokeout,While,While,When,When,When,When,Exercises,7.Iwaswalkinginthestreettheaccidenthappened.8.youhaveameeting,youshouldturnoffyourmobilephone.youhavePEclass,youshouldwearsportsshoes.Iwasdoingmyhomework,thephonerang.itwasraining,theplanetookoff.theteacherwasspeakingtoclass,hestoodupsuddenly.,when,When,When,While,While,While,谢谢观赏,Whataredreams