Mary didn’t understand made her deskmate so upset all the morning.
A. it was that
B. why it was that
C. how that was
D. what it was that
网友回答
A. it was that
B. why it was that
C. how that was
(答案→)D. what it was that
解析：本题考查强调句型。该题为特殊疑问句整体做understand的宾语，因此应该使用正常语序。由于made her deskmate so upset缺少主语，因此我们可以断定“被强调部分”是做主语的，因此应该使用疑问代词what。