I was to have made a speech if _________.

A. I was not called away

B. nobody would have called me away

C. I had not been called away

D. nobody called me away

請問老師，這題if引導非真實條件句，為何主句又用的過去以后完成時？還有請問如何區別陳述語氣的時態和虛擬語氣呢？

提前謝謝老師！?

I was to have made a speech if I had not beencalled away.

sb was to have done sth 這個結構表示某人本來計劃或安排在過去做某事，但因為某種緣由沒做某事。一般后面用but引導并列分句講解緣由是什么，but后分句用陳述語氣表示事實。比如，I was to have made a speech, but I had been called away. 本句沒用but分句，而是用了if虛擬條件句，if從句用虛擬語氣表示與事實相反的假設。注意這個if從句并非修飾謂語動詞was, 而是修飾不定式完成體的，是不定式短語的內部結構，所以這個if從句是不能放在句首的。