与将来事实相 反的假设
过去式（be--were） should / would/
should do
could / might + do
were to do
1.如果我是你，我会接受他的建议（现在虚拟） If I were you, I would accept his advice.
2.如果明天下雨，我会待在家里。（将来虚拟）
A.Were
B. Should
C.Would
D. Will
If it should rain tomorrow (省略if，用部分倒装）
2.错综时间虚拟语气
当从句与主句时间不一致时，动词的形式要根 据它所表示的时间作出相应的调整。
If you __ha_d__fo_ll_ow_e_d___(follow)my advice just now, you __w_o_u_ld_b_e__(be)better now.
Should it rain tomorrow,…….
3.If you had studied hard before, you would have passed the exam. Had you studied hard before,……
________ it rain tomorrow, we would have to put off the visit to the Yang Pu Bridge.
He hesitated for a moment before kicking the ball, otherwise he _____ a goal.
A.had scored B.scored C.would score D.would have scored
1.I was ill that day. Otherwise, I would have taken part in the sports meeting.
=If I hadn't been ill that day, I would have taken part in the sports meeting.
Without electricity, human being life ______ quite different today.
A.is B.will be C.would have been D.would be
But for his help, I ______. A.should not have succeeded B.have not succeeded C.did not succeed D.had not succeeded
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2.He telephoned to inform me of your birthday, or I would have known nothing about it.
3.Without / But for your help, we couldn' t have finished the work ahead of time. =If it had not been for your help, …
1. if从句中， 省略if，were，had，should可以放在句 首，（用于倒装结构）， 否定词not不能放在前面。
1.If I were you, I would accept his advice. Were I you,……
2.If it should rain tomorrow, I would stay at home.
虚拟语气
概念：
虚拟语气：表示说话人所说的不是事实， 而是一种愿望、假设、或推测。
一、虚拟语气在 if非真实条件句中
虚拟条件 从句(If)
主句
与现在事实相 反的假设
过去式 be --were
should / would/ could / might + do
与过去事实相 反的假设
had done
should / would/ could / might + have done
If you __h_a_d_s_tu_d_ie_d_(study)hard before, you _w_o_u_ld_b_e_(be)a college student now.
If you ______ with George earlier, you _____ so angry now.
If it rained（should rain/were to rain ）tomorrow, I would stay at home. 3.如果你以前好好学习， 你会通过考试的。 If you had studied hard before, you would have passed the exam. （过去虚拟）
A.talked; would not be B.had talked; would not be C.would talk; would not be D.had talked; would not have been
If we had taken such effective measures much earlier, the river _____ so seriously now.
You didn' t let me drive. If we ______ in turn, you ______ so tired.
A.drove; didn' t get B.drove; wouldn' t get C.were driving; wouldn' t get D.had driven; wouldn' t have got
A.is not polluted
B.would not be polluted
C.had not been polluted
D.would not have been polluted
3、含蓄虚拟语气 在虚拟语气中，并不总是出现if引导的条件句， 而通过其它手段来代替条件句。 常用的有otherwise ，or ，without，but for（倘没 有，要不是）等。