He kept smiling secretly and we were all wondering that made him so happy.
A. how it did
B. what he did
C. how it was
D. what it was
网友回答
A. how it did
B. what he did
C. how it was
(答案→)D. what it was
解析：本题考查强调句。本题考查强调句的特殊疑问句形式。宾语从句中缺少主语，故用what。根据句意选择D。