联合国HDI的中文含义是（），用来评估和比较世界不同国家不同时期在健康、知识和收入三个重要领域的进步。 ["A.国民生产总值","B.国家发展指数","C.社会发展指数","D.人类发展指数"]
In an open lifeboat，the lifeboat compass is usually（）. ["placed in a fixed bracket when being used","clamped to any position convenient for the coxswain to see it","permanently mounted on the lifeboat's centerline","mounted in the center of the boat to eliminate deviatio"]
某旅行社与游客签订了“新马泰港澳游”合同，出团前因旅行社未办妥旅游签证而无法正常出行。游客提出退团要求，当时正值泰国政局动荡期间，红衫军与政府冲突不断，旅行社以遭遇不可抗拒的情况为由，拖延退款。游客遂想当地旅游质监所进行投诉，要求全额返还所交团款。旅行社的辩解是否合理？
在市场经济条件下，经济人最基本的天性就是（） ["机会主义","自由主义","损人利己","竞争逐利"]
（）是和Active directory有关的。 ["DNS服务","安全日志","目录服务日志","文件复制服务日志"]
简述潮流分布的概念。
