【题目】What is known to all is that up to now China has made a great ________ to preserving the peace.
A. conclusionB. commentC. campaignD. contribution
在线课程【答案】D
【解析】
试题分析：考查名词辨析。conclusion结论；comment评论；campaign战役；contribution贡献。句意：众所周知的是，到目前为止中国为维护和平做出了很大贡献。D项符合语境。