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

问题补充：

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

A. sitting

B. sit on

C. sit

D. being sat on

答案：

A. sitting

(答案→)B. sit on

C. sit

D. being sat on

解析：句意：椅子看起来相当硬，但事实上坐在上面是非常舒适的。英语中，有些动词是主动的形式表被动的含义，当指物质的特性时主动表被动！eg. The book sold well.书卖得好！ 此处也是，指的是椅子的特性，故用主动表被动。另外，坐在椅子上，sit是不及物动词，后面加介词on与the chair做宾语。所以on不可省略，故选B。

考点: 考查非谓语动词的用法。