虚拟语气 i didn't know his telephone number.____ it,I ______ theni didn't know his telephone number.____ it,I ______ thenA.Had I known; would ring him upB.Should I know ;would have ring him upC.If I knew ;would ring him upD.Had I know; would have

虚拟语气 i didn't know his telephone number.____ it,I ______ theni didn't know his telephone number.____ it,I ______ thenA.Had I known; would ring him upB.Should I know ;would have ring him upC.If I knew ;would ring him upD.Had I know; would have
虚拟语气 i didn't know his telephone number.____ it,I ______ then
i didn't know his telephone number.____ it,I ______ then
A.Had I known; would ring him up
B.Should I know ;would have ring him up
C.If I knew ;would ring him up
D.Had I know; would have rung him up

虚拟语气 i didn't know his telephone number.____ it,I ______ theni didn't know his telephone number.____ it,I ______ thenA.Had I known; would ring him upB.Should I know ;would have ring him upC.If I knew ;would ring him upD.Had I know; would have
A
这个~虚拟语气其实也很好理解的.这样想吧.
前面用的过去时,他假设过去的时候他知道电话号码,那么那个时候他将会给他打电话.
所以前面是Had I known,正确的语序是I had known,这是过去完成时,假设在过去我已经知道了他的号码.
I would do ,应该是接当时的情况,我如果当时知道了号码,我将会做那件事.第4个选项,意思是我将会已经完成了某件事,跟语境是不符合的.