数据库规定：能够唯一标识某一记录属性的字段叫（）。
A、数据库结构
B、记录
C、字段
D、关键字
参考答案：D
Jack had a wonderful time _____one place after another in Beijing and he had much time _____the city.[ ]
A. to visit, to enjoy
B. visiting, to enjoy
C. to visit, enjoying
D. visiting, enjoying
( )是团体心理咨询之父。
A．普拉特
B．佩特森
C．艾根
D．梅肯鲍姆
