在关系模式R(U)中,如果X→Y,Y→Z,且Y不是X的子集,不存在X←→Y的情况,则称Z 【15】 依赖于X。
参考答案:传递
解析: 本题考查函数依赖的基本知识,参见4.4.1节。
Our monitor requested that ________.
A.all the class studied more carefully the problem
B.the problem was more carefully studied
C.with great care the problem could be studied
D.all the class study the problem more carefully
检查交通静脉瓣膜功能的试验有
A.Trendelenburg试验Ⅰ
B.Trendelenburg试验Ⅱ
C.Perthes试验
D.Thomas试验
E.Pratt试验