用来表示说的话不是事实,或者是不可能发生的情况,而是一种愿望、建议、假设的语气叫虚拟语气
(一)if主从句中的虚拟语气【完成例句】(1)如果我是你,我会接受邀请的
IfIwereyou,Ishouldaccepttheinvitation
(2)如果我有空,我就去那儿
IfIhadtime,Iwouldgothere
【结论1】条件与现在事实相反从句谓语用一般过去时(be多用were)主句谓语用would/should/could/might+动词原形【完成例句】(3)如果你早点来,你就不会错过那辆公共汽车了
Ifyouhadcomeearlier,youcouldn't/wouldn'thavemissedthebus
(4)如果他昨天见到了你,他就会还你的书的
Ifhehadseenyouyesterday,hewouldhavereturnedyourbook
【结论2】条件与过去事实相反从句谓语用haddone主句谓语用would/should/could/might+havedone【完成例句】(5)万一明天下雨,运动会就推迟
(事实上明天下雨的可能性不大
)Ifitshouldrain/weretorain/rainedtomorrow,thesportsmeetwouldbeputoff
(6)万一杯子掉下来会打碎的
Ifyoudropped/shoulddrop/weretodroptheglass,itwouldbreak
【结论3】条件与将来事实相反从句谓语用一般过去时(be多用were)或should+动词原形/weretodo主句谓语用would/should/could/might+动词原形【疑难1】含蓄虚拟句(即含有without/butfor,otherwise/or等词的句子)【例句观察】Humanbeingswouldd