He ______ at the meeting, but his heart attack prevented him.
A.will speak B.is going to speak
C.had to speak D.was going to speak
He ______ at the meeting, but his heart attack prevented him.
A.will speak B.is going to speak
C.had to speak D.was going to speak
D
由题意“他本来打算在会上发言，但……”可知应该用过去将来时，只有D是过去将来时的形式。