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if引导的条件句三种情况

2020-08-05 16:35:27文/王君婷

1.对现在虚拟:条件句:一般过去时主句:could/would/+动词原形。2.对过去虚拟:条件句:过去完成时主句:could/would have done。3.对将来虚拟:条件句:1.were to do;2.should do;3.一般过去时:主句could/would/+动词原形。

if引导的条件句三种情况

一、对现在情况的虚拟条件从句中谓语动词用一般过去式,主句用“would/should/might/could+动词原形”形式,表示对现在不可能实现情况的假想。If I were you,I would choose to work in a small town.如果我是你,我会选择在小城镇工作。(事实上我不是你)If I had a map now,we could easily get out of the forest.如果现在有地图,我们能很容易地走出森林。(事实上是现在没有地图)注意:在条件从句中,如果谓语动词是be的形式,不管主语是单数还是复数,书面语中用were,而口语中如果是单数,也可以用was,不过在if I were...中一般用were.If the world were perfect,how could we enjoy the pleasure and comfort of being successful?世界若完美,我们如何能尝到创造成功的快慰?

二、对过去情况的虚拟条件从句中谓语动词用过去完成式,主语用“would/could/should/might+have+动词的过去分词”形式。If it had not been for your help yesterday,I could not have caught the bus.如果昨天没有你的帮助,我不会赶上公交车。(事实是你昨天已经帮助了我,所以我赶上了车)

三、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表示的可能性最大,动词过去式的可能性次之,were to do 的可能性最小。If things were to be twice,all would be wise.假如凡事都可以重新做一次,人人皆可成为聪明人。

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