They looked at his burnt clothes and didn’t know to do. A. sad; what B. sadly; how C. sa

问题补充：

They looked at his burnt clothes and didn’t know to do.

A. sad; what

B. sadly; how

C. sadly; what

D. sad; how

答案：

A. sad; what

B. sadly; how

(答案→)C. sadly; what

D. sad; how

解析：本题考查词性及关系词。look为动词，故用副词修饰，根据句意是：不知道做什么？故用what。选C。