Mr. Smith didn’t understand made his son so upset that evening.
A. what was it
B. why it was this
C. how that was
D. what it was that
网友回答
A. what was it
B. why it was this
C. how that was
(答案→)D. what it was that
解析：考查强调句型it be +被强调部分+that…;又因为句中缺少understand的宾语从句的主语所以用what，选D. 史密斯先生不知道那晚到底是什么事情使得他的儿子如此伤心。