When was it you met Yao Ming in the street?A. asB. ifC. whileD. that

问题补充：

When was it you met Yao Ming in the street?

A. as

B. if

C. while

D. that

答案：

A. as

B. if

C. while

(答案→)D. that

解析：考查it 用法中的强调句式。