There was a knock at the door. It was the second time someone ______ me that evening.
A. had interrupted
B. to have interrupted
C. would have interrupted
D. to interrupt
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为了方便人们记忆、阅读和编程,汇编语言将机器指令采用助记符号表示。
A. 对
B. 错
在一个部门应用系统中,其数据库中的每个二维表是用具体的“关系数据模式”说明。其形式为:R(A1,A2,…,Ai…,An)。其中R和Ai分别表示______。
A. 关系模式名和属性名
B. 关系联系名和属性名
C. 关系模式名和关系联系名
D. 关系约束名和属性名
The spellings of many Old English words have been ______ in the living language, although their pronunciations have changed.
A. preserved
B. preempted
C. revised
D. improved
在描述数据传输速率时,常用的度量单位Mb/s是kb/s的______倍。