记忆障碍在脑器质性精神障碍的早期主要表现为（ ）。
A．顺行性遗忘
B．逆行性遗忘
C．错构
D．虚构
E．近事遗忘
参考答案：E
Some teachers often give their students too much work to do, ________that they will thus improve
their school grades.
A. hoping
B. to hope
C. hope
D. hoped
关系表中的每一横行称为一个
A．元组
B．字段
C．属性
D．码
