【单选题】【消耗次数：1】
If we hadn’t got a lift, we ____ the top flat so soon.
①
would not reach
②
can not reach
③
could not have reached
④
will not reach
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相关题目
【简答题】
Direction: Fill in the blanks with thephrases given below. Change the form if necessary.[ought to; look forward to; in wonder; give way to; look down; on the way to; reach out; put one’s arm around; trip over; cut into]6. We[填空1]hearing from you soon.
【单选题】
We have reached an agreement we should invest in the Internet-related business.
①
what
②
where
③
that
④
as
【单选题】
We’ll _____you as soon as we have any further information.
①
notify
②
signify
③
communicates
④
impart
【单选题】
______ the storm, we should have reached our company.
①
Because of
②
In spite of
③
In case of
④
But for
【单选题】
Dieters should try to reach and __________ a reasonable weight.
①
contain
②
secure
③
reserve
④
maintain
【单选题】
We were all surprised when he made it clear that he _____________office soon.
①
leaves
②
would leave
③
left
④
had left
【单选题】
In a sudden _____ of anger, the man tore up everything within reach.
①
attack
②
burst
③
split
④
blast
【单选题】
As we can no longer wait for the delivery of our order, we have to ____ it.
①
postpone
②
refuse
③
delay
④
cancel
随机题目
【判断题】
设<img class=jc-formula data-tex=\alpha src=https://huaweicloudobs.ahjxjy.cn/DEFDC04456737669FDEF7C42924B9B9C.png style=vertical-align: middle;/>是某一方程组的解向量，<img class=jc-formula data-tex=k src=https://huaweicloudobs.ahjxjy.cn/88383F685E0988F317F08CF98D04960A.png style=vertical-align: middle;/>为某一常数，则<img class=jc-formula data-tex=\alpha src=https://huaweicloudobs.ahjxjy.cn/DEFDC04456737669FDEF7C42924B9B9C.png style=vertical-align: middle;/>也为该方程组的解向量.
①
正确
②
错误
【判断题】
<img class=jc-formula data-tex=A src=https://huaweicloudobs.ahjxjy.cn/53F870B8D448BB3DB08A67264B6329F9.png style=vertical-align: middle;/>为<img class=jc-formula data-tex=m\times n src=https://huaweicloudobs.ahjxjy.cn/68A6AD364CE4B73E12720634B9824451.png style=vertical-align: middle;/>型矩阵，则当<img class=jc-formula data-tex=R(A)=n src=https://huaweicloudobs.ahjxjy.cn/1E513F3E976CAD5E8D5ACEEE51943C73.png style=vertical-align: middle;/>时，<img class=jc-formula data-tex=Ax=b src=https://huaweicloudobs.ahjxjy.cn/B2E6B7847F647AEBDF186E16122B2E40.png style=vertical-align: middle;/>有唯一解.
①
正确
②
错误
【判断题】
向量<img class=jc-formula data-tex=\alpha src=https://huaweicloudobs.ahjxjy.cn/DEFDC04456737669FDEF7C42924B9B9C.png style=vertical-align: middle;/>线性相关<img class=jc-formula data-tex=\Leftrightarrow src=https://huaweicloudobs.ahjxjy.cn/65980352270B8F43A0D41A07B3CE4CB1.png style=vertical-align: middle;/>它是任一向量组的线性组合.
①
正确
②
错误
【判断题】
任意一个非齐次线性方程组<img class=jc-formula data-tex=AX=B src=https://huaweicloudobs.ahjxjy.cn/EEB1872ED54868931D0713F57B2E76B4.png style=vertical-align: middle;/>都不存在基础解系.
①
正确
②
错误
【单选题】
若矩阵A的列向量组线性无关，则方程组<img class=jc-formula data-tex=AX=0 src=https://huaweicloudobs.ahjxjy.cn/CEC806624F9D642E698219EC94F94B3E.png style=vertical-align: middle;/>[填空].
①
有非零解
②
只有零解
③
无解
【单选题】
设含有m个未知数，n个方程的齐次线性方程组<img class=jc-formula data-tex={ A }_{ n\times m }x=o src=https://huaweicloudobs.ahjxjy.cn/E4F50AB1F05EF4540024B5942B512977.png style=vertical-align: middle;/>有非零解，则[填空].
①
R(A)m
②
R(A)m
③
R(A)=m
【单选题】
已知<img class=jc-formula data-tex=n src=https://huaweicloudobs.ahjxjy.cn/6593C84B94B8062EB35F270378D7D9B6.png style=vertical-align: middle;/>阶矩阵<img class=jc-formula data-tex=A, src=https://huaweicloudobs.ahjxjy.cn/5A79F9EC526E0C33CC320B9CFD03BD2C.png style=vertical-align: middle;/>则<img class=jc-formula data-tex=R(A)=n src=https://huaweicloudobs.ahjxjy.cn/1E513F3E976CAD5E8D5ACEEE51943C73.png style=vertical-align: middle;/>的充要条件是<img class=jc-formula data-tex=(A+B)(A-B)={ A }^{ 2 }-{ B }^{ 2 } src=https://huaweicloudobs.ahjxjy.cn/B3AE6C9467A5CA05232F0CC60E696AFF.png style=vertical-align: middle;/>
①
<img class=jc-formula data-tex=\left| A \right| =0 src=https://huaweicloudobs.ahjxjy.cn/C0FF5500641DFC6CB166CD5F7867609E.png style=white-space: normal; vertical-align: middle;/>
②
<img class=jc-formula data-tex=\left| A \right| \neq 0 src=https://huaweicloudobs.ahjxjy.cn/DDF5A5E8A4C1CB242AB871222A74D4F9.png style=vertical-align: middle;/>
③
不确定
【单选题】
设<img class=jc-formula data-tex=A src=https://huaweicloudobs.ahjxjy.cn/53F870B8D448BB3DB08A67264B6329F9.png style=vertical-align: middle;/>是4×3矩阵，若齐次线性方程组<img class=jc-formula data-tex=AX=0 src=https://huaweicloudobs.ahjxjy.cn/CEC806624F9D642E698219EC94F94B3E.png style=vertical-align: middle;/>只有零解，则矩阵<img class=jc-formula data-tex=A src=https://huaweicloudobs.ahjxjy.cn/53F870B8D448BB3DB08A67264B6329F9.png style=vertical-align: middle;/>的秩为[填空].
①
1
②
2
③
3