问题
选择题
She looks sad. Could you please tell me ____ that prevents her from being as happy as before?
A．what it is
B．it is what
C．how it is
D．it is how
答案
答案：A
本题含有强调句型，若把It is···that去掉，则很容易地看出what引导的宾语从句，what在从句中充当主语。故选A。