Make a tentative guess Peking Man have done and used thousands of years ago.A. that; may

问题补充：

Make a tentative guess Peking Man have done and used thousands of years ago.

A. that; may

B. that; must

C. what; may

D. what; should

答案：

A. that; may

B. that; must

(答案→)C. what; may

D. what; should

解析：考查名词性从句和去运动场。句意“试着猜测一下，几千年前，北京人可能做了什么事，用的什么工具。”guess后跟的宾语从句，从句的done和used缺少宾语，故用what，既然是猜测，应该用may。故选C。