When a space shuttle has accomplished its , it can be ready for another trip in about two

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A. venture
(答案→)B. mission
C. mission
D. responsibility
解析：　　本题译文：当航天飞机完成了它的使命，它能在大约两周内做好准备再次航行。mission通常指一种特殊的、特定的且有一定难度的使命或工作，常与acplish, plete等词搭配，如：acplish a historic mission完成一项历史使命。Venture冒险；常指商业上的冒险投机。例如：He declined the business venture. Commission委任；代理；佣金。He often goes beyond his mission.(他时常越权。)responsibility责任。