1、从句：If+主语+had+done。2、主句：主语+should/would/might/could+have done。3、例句：If he had taken my advice，he would not have made such a mistake。表示与将来事实相反：1、从句：if+主语+were to do。

If you go with me, you shall be rewarded.2. 当if后面接一般过去时的动词时,则是一种虚拟语气.if sb did sth sb would/should do sth.If I didn't make that mistake, I would't have suffered such a fail...

1、对现在情况的假设：表示说话时不存在或与事实相反的情况。形式：If+主语+did，主语+should/ would /could +do.例句：If you knew english well,you would be able to talk with foreigners freely.2、对过去情况的假...

if虚拟语气的用法归纳如下：一、表示与现在事实相反的情况：1、从句：If主语过去时（Be动词用were）。2、主句：主语 should/would/could/might do。3、例句：（1）If I were you，I would take an umbrella.如果我是你...

形式如下：if虚拟语气的三种形式：对现在情况的虚拟、对过去情况的虚拟、对将来情况的虚拟。在表示与将来事实相反的条件从句中，谓语动词可用should do,were to do或动词的过去式三种形式表示，但意义略有不同。should表示的...

1.当if后面接一般现在时的动词时,表示对将来的一种推测.if sb do sth sb will/shall do sth.if you go with me,you shall be rewarded.2.当if后面接一般过去时的动词时,则是一种虚拟语气.if sb did sth sb wo...

+ do（动词原型）对将来的虚拟：从句1) if + should + do（动词原型）; 2) if + were to +do（动词原型）; 3) if + did（过去式）; 主句 would/could/should/might + do（动词原型）...

if虚拟语气的三种形式：①对现在情况的虚拟、②对过去情况的虚拟、③对将来情况的虚拟。1.对将来情况的虚拟 主句：主语＋would/should/might/could＋动词原形 从句：should＋动词原形/were to＋动词原形。2.对现在情况的虚拟...

if虚拟语气的三种时态如下：1、对目前状况的虚拟 条件从句中谓语动词用一般过去时，主句用“would/should/might/could+动词原形”方式，表明对目前不太可能实现状况的幻想。If I were you,I would choose to work in a ...

if从句的虚拟语气原理：1、如果句子在想象现在发生而实际未发生的事件，由现在时倒退成过去时：（从句）if+过去时，（主句）4个情态动词+动词原形 2、如果句子在想象将来发生而实际不会发生的事件，由将来时倒退成过去时，...