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【单选题】
CD 唱机不能进入正常工作状态,聚焦镜头没有动作,激光头不能上下移动,应当检查()。A.
驱动电路和电动机
B.
聚焦驱动器
C.
调谐回路
D.
伺服系统
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举一反三
【单选题】Bob ______ hard, otherwise he ______ this exam.
A.
must have worked, would fail
B.
mustn't have worked, wouldn't fail
C.
can't work, wouldn't have failed
D.
can't have worked, wouldn't have failed
【简答题】用所给单词填空 This was ______ he didn't come. The question is ______ you should do next. The problem is ______ would go there. What shall we do ______ it rains this afternoon. I was very thirsty , ______ I ...
【单选题】What did the writer learn about from his first job?
A.
He could work as hard as possible.
B.
He could go to work on time.
C.
He should never fail to go to work.
D.
He should be respectful and loyal to the people he works for.
【简答题】在数据库的三级模式体系结构中，外模式与概念模式之间的映像，实现了数据库的独立性。
【简答题】在数据库的三级模式体系结构中，外模式与模式之间的映射实现了数据库的________独立性。
【简答题】在数据库的三级模式体系结构中，外模式与模式之间的映象(外模式/模式)，实现了数据库的【 】独立性。
【单选题】You shall fail if you don't work hard. He shall come back at once . shall在上两句话中表什么意思。
A.
应当
B.
将要
C.
警告，告诫
D.
必须
【简答题】在数据库的三级模式体系结构中，外模式与模式之间的映像(外模式/模式)，实现了数据库【 】独立性。
【简答题】在数据库的三级模式体系结构中，外模式与模式之间的映像实现了数据库的______独立性。
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