单项选择题

学校数据库中有学生和宿舍两个关系：
学生（学号，姓名）
宿舍（楼名，房间号，床位号，学号）
假设有的学生不住宿，床位也可能空闲。如果要列出所有学生住宿和宿舍分配的情况，包括没有住宿的学生和空闲的床位，则查询时这两个表应执行（）。 A. 内连接 B. 左外连接 C. 右外连接 D. 全外连接

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单项选择题

Which of the following is not included in Theory X assumptions? A.
Average human beings have an inherent dislike of work and will avoid it fi they can. B.
Because of this human characteristic of disliking work, most people must be coerced, controlled, directed, and threatened with punishment to get them to put forth adequate effort toward the achievement of organizational objectives. C.
Average human beings prefer to be directed, wish to avoid responsibility, have relatively little ambition, and want security above everything else. D.
The expenditure of physical and mental effort in work is as natural as play or rest.

It is difficult to cure high blood pressure, but it can be effectively controlled through the comprehensive management of the condition. Don not stop taking medicine rashly.

答案：正确