31. The chair looks rather hard but in fact it is very comfortable to.A. sitB. sit onC. be

问题补充：

31. The chair looks rather hard，but in fact it is very comfortable to.

A. sit

B. sit on

C. be sat

D. be sat on

答案：

A. sit

(答案→)B. sit on

C. be sat

D. be sat on

解析：可联系答案网客服索取此答案。