对理论性、知识性较强的物业管理专业培训效果进行考核的最佳方法是（）。
A．笔试
B．口试
C．技能竞赛
D．实际操作
参考答案：A
The boy ______ his friends was playing in the street when the earthquake happened. [ ]
A. with
B. and
C. as well as
D. as far as
当下述哪一条成立时，称X→Y为平凡的函数依赖
A．X包含于Y
B．Y包含于X
C．X∩Y=￠
D．X∩Y≠￠
