问题补充:
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
答案:
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。