– What a hard chair!Yes it is. But in fact it is very comfortable to .A. sitB. sit on

问题补充：

– What a hard chair! --Yes, it is. 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：sit是不及物动词，“坐在椅子上”用sit on，先排除A、C；根据句意“多么解释的椅子啊！”“是的，但事实上，坐起来也很舒服。”sit的逻辑主语是人，是主谓关系，故用sit on。故选B。