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【多选题】
下面对于关系数据库中表的主键描述正确的是（ ）。A.
使用主键可以唯一地标识表中的一行数据
B.
键的值可以为空值
C.
能唯一标识一行记录的列只有主键
D.
在一个表中主键列的值是唯一的
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举一反三
【单选题】Fortunately he will go on holiday in place of Brown ．
A.
．不填； the
B.
．不填；不填
C.
．不填； a
D.
． the ；不填
【单选题】The president of the country ______ him to be the Secretary of State.
A.
elected
B.
nominated
C.
voted
D.
notified
【简答题】A．ambitiously B．aggressively C．substantially D．fortunately
【单选题】When Secretary of State Condoleezza Rice stood beside Afghan President Hamid Karzai, she made an enlightened statement about cutting Afghanistan' s opium production, saying: 'It is a problem that took...
A.
Opium is closely related with the economy situation of Afghanistan people.
B.
It is a hard job which needs time.
C.
Afghanistan is not a democratic country.
D.
It is a problem left by history and it need more patience.
【简答题】A．Especially B．Probably C．Suddenly D．Fortunately
【单选题】听力原文： Secretary of State, Warren Christopher, has wrapped up his latest trip to the Middle East, saying the peace process is progressing. Mr. Christopher says he will leave the region Thursday, assure...
A.
believes there is hope for peace.
B.
will report to the UN on Thursday.
C.
will hold more talks before leaving the region.
D.
is not sure that the peace process will succeed.
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