题目内容：

The teacher asked the students______
A.if they were interested in dinusaurs
B.when was Albert Einstein born
C.what they will do with the computers
D.how many trees they have planted
问：为什么选A而不选D?

优质解答

正确：A
宾语从句时,主句为一般过去时时,从句通常套用过去时态的某种形式.如果D的have改为had,则也是正确的.