在设计决策支持系统时，要求系统能回答用户的问题类型是（）
A、查询问题
B、排序问题
C、“如果„则„”问题
D、统计问题
参考答案：C
—The sweater is very nice. I'll take it.
—But you'd better ________ first. I think it is a little large for you. [ ]
A. pay for it
B. put it on
C. put it off
D. try it on
机械密封出现突然漏失的原因是什么？
