英语语法知识点详解零条件句

英语语法知识点详解零条件句InEnglish,therearefourtypesofconditionalsentences:英语中有四大类型条件句：0-TheZeroConditional零条件句一TheFirstConditional第一类条件句-TheSecondConditional第二类条件句一TheThirdConditional第三类条件句EachconditionalsentencehasanIFclause,andamainclause.AndallthefourtypesofconditionalsusetheconjunctionIF.条件句由两个组成部分：IF从句+主句。四大类型条件句均使用连词IF。IFclauseMainclauseIF从句 主句0IF+presentpresentsimpletotalkaboutpermanenttruths,suchsimple, 一般现在时 asscientificfacts,andgeneralhabitsIF+一般现 谈论客观真理，如科学事实，和一般在时， 的习惯★Ifyouheatwater,itevaporates.

★如果你加热水，水就会蒸发。1stIF+presentwill+infinitivetotalkaboutpossibleandlikelyfuturesimple, will+动词不定outcomesIF+一般现 式 谈论将来可能发生的情况在时，★Ifyoustudyhard,youwillpasstheexam.★如果你努力学习，你将通过考试。2ndIF+pastsimple,IF+2ndIF+pastsimple,IF+一般过去时，would+infinitivewould+动词不定式totalkaboutimprobableorimpossiblesituationsinthepresentorfuture谈论现在或将来不可能发生的情况与现在事实相反（非真实条件句）★IfIwonthelottery,Iwouldbuyabighouse.★如果我中彩票了，我会买一栋大房子。3rdIF+pastperfect,IF+过去完成时，3rdIF+pastperfect,IF+过去完成时，wouldhave+pastparticiplewouldhave+过去分词todescribeaneventforthepastthatdidnothappen描述过去未发生的事情与过去事实相反（非真实条件句）★IfIhadstudiedharder,Iwouldhavepassedtheexam.★如果我当时更努力地学习，我早就通过考试了。TheIFclausegivesustheconditionorsituation,andthemainclausegivesustheresult.TheZeroandtheFirstConditionalexpressrealorpossibleconditionsandresults.TheSecondandtheThirdConditionalexpressimpossible,hypothetical,unrealconditionsandresults.IF从句提供条件或情况，主句描述产生的结果。零条件句和第一类条件句描述真实或可能发生的条件和结果。第二类条件句和第三类条件句描述不可能发生的、假设的、不真实的条件和结果。Withallconditionalsentences,theorderoftheseclausesisnotfixed.So,youcanswapthemaround.Andevenwhenyouchangetheorderoftheclauses,themeaningisthesame.Inwriting,ifyourIFclausecomesfirst,addthatcomma.Ifyourmainclausecomesfirst,youdon’tneedacomma.在所有类型的条件句中，IF从句和主句的顺序可以互换。即使句子的顺序发生改变，其含义也不会发生变化。在书写中，如果把IF从句放在句首，中间加个逗号，再加主句。如果主句放在句首，则无需加句号。IfIpractice,Iwillgetbetter.IwillgetbetterifIpractice.TheZeroConditional零条件句AZeroConditionalsentenceconsistsoftwopresentsimpleverbs.Bothpartsofthesentenceareinthepresenttense.零条件句的IF从句和主句均由一般现在时的动词引导。Ifthisthinghappens,thatthinghappens.IF+一般现在时，一般现在时WeusetheZeroConditionaltotalkaboutpermanenttruths,suchasscientificfacts,andgeneralhabits.谈论客观真理，如科学事实，和一般的习惯。Ifyouheatwater,itevaporates.如果你加热水，水就会蒸发。Ifyouleaveicecreaminthesun,itmelts.如果你把冰激凌放在太阳下，它就会融化。Peopledie,iftheydon’tdrinkenoughwater.如果人们不喝足够多的水，就会死亡。Ifyouputastoneinwater,itsinks.如果你把石头放在水里，它就会沉下去。Ifyoueatalot,youputonweight.如果你吃得多，你就会发胖。YoucanusuallyreplaceIFwithWHENORWHENVER,withoutthemeaningchanging.这里的IF可以用WHENORWHENVER替代，而不会改变其意义。WeoftenusetheZeroConditionaltogiveinstructions,withtheimperativeinthemainclause.“零条件句”可以用来发出指令，主句使用祈使句。