The teachers always complain about the children in class. A. to teach tiredB. teaching t

问题补充：

The teachers always complain about the children in class.

A. to teach, tired

B. teaching, tired

C. teaching, tiring

D. to teach, tiring

答案：

A. to teach, tired

(答案→)B. teaching, tired

C. teaching, tiring

D. to teach, tiring

解析：complain about doing sth是固定搭配；劳累的孩子应用tired来修饰。