已知三阶矩阵$A$满足$\mid A-E\mid=\mid A-2E\mid=\mid A-3E\mid=0$，则$\mid A\mid$=( )。 A: $4$ B: $6$ C: $12$ D: $3$

设$A,B$是$n$阶正交矩阵，且$\mid A\mid=-\mid B\mid$，则( ). A: $A+B$可逆 B: $A+B$不可逆 C: $\mid A+B\mid=1$ D: $\mid A+B\mid=-1$

They will be back home（） A: a week later B: after a week C: in a week D: a week

16.As he is not in good health, he goes to his factory only ______ just to learn something about the progress of experiment.　　a. once a week b. one week c. one time a week d. one a week A: once a week B: one week C: one time a week D: one a week

请选出世界四大著名时装周 A: Milan Fashion Week B: Japan Fashion Week C: Paris Fashion Week D: Shanghai Fashion Week E: New York Fashion Week F: London Fashion Week

Excel2010从18份身份证号中获取出生日期可以使用（）函数。 A: MID(A1,6,8) B: MID(A1,7,8) C: =MID(A1,6,8) D: =MID(A1,7,8)

船舶电台海上移动业务识别码的组成是( )。 A: MID X1X2X3X4X5X6 B: 0 MID X1X2X3X4X5 C: 00 MID X1X2X3X4 D: 00 MID X1X2X3X4X5

如果A1单元格中有某人的身份证号，如何提取他的出生年月日 A: mid（A1,7,4） B: mid（A1,4,7） C: mid（A1,7,8） D: mid（A1,8,7）

The shirt（）was very expensive. A: bought last week B: he bought week C: which he bought it last week D: he bought last week

—How long have you been ill —______（）. A: Since last week B: A week ago C: Once a week