When a space shuttle has accomplished its （），itcan be ready for another trip in about two weeks.

A．It had caused embarrassment to the British government.B．It had brought her closer to the ordinary people.C．It had greatly promoted her popularity.D．It had affected her relations with the British government.

A.It
B.
B．It
C.
C．It
D.
D．It
E.

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设A为n阶矩阵，将A的第i，j行互换后再将第i，j列互换得到矩阵B，则“A与B等价”，“A与B相似”，“A与B合同”中成立的关系共有( )个．A．0B．1C．2D．3 点击查看答案