Sitting at the corner of the meeting room he looked sad because there were so many proble

问题补充：

Sitting at the corner of the meeting room, he looked sad because there were so many problems .

A. remaining to settle

B. remained settling

C. remaining to be settled

D. remained to be settled

答案：

A. remaining to settle

B. remained settling

(答案→)C. remaining to be settled

D. remained to be settled

解析：选C考查非谓语动词。句意：坐在会议室的角落里，他看起来很伤心，因为仍然有许多问题需要解决。remain在there be结构中作后置定语，由于remain是不及物动词，故应用现在分词remaining；且settle与problems之间构成动宾关系，故用动词不定式的被动形式。remain之后接动词不定式表示动作还未完成。