问题
选择题
Mr. Green didn’t understand ________ made his daughter so absent-minded this morning.
A．how that was
B．what was it
C．why it was that
D．what it was that
答案
答案：D
考查强调句的疑问形式。根据题意可知，宾语从句中缺少主语，故用what引导其强调句，选D。