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【单选题】
n阶实对称矩阵A正定的充分必要条件是( )A.
二次型x\r\n T \r\nAx的负惯性指数为零。
B.
存在可逆矩阵P使P\r\n 一1 \r\nAP=E。
C.
存在n阶矩阵C使A=C\r\n 一1 \r\nC。
D.
A的伴随矩阵A\r\n * \r\n与E合同。
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举一反三
【单选题】According to the passage, what is the real 'leadership'?
A.
Asking followers to obey whatever the leaders tell them.
B.
Organizing people to share opinions and intelligence.
C.
Asking employers to give the only exact solution or answer.
D.
Gaining formal authority and implementing it on others.
【多选题】甲公司欲与某外国公司设立一中外合资经营企业，就相关事项咨询律师。下列选项错误的是（ ）。
A.
合资企业自审批机关批准之日起成立
B.
合资企业章程中可以约定由公司总经理担任公司的法定代表人
C.
合资企业作为有限责任公司应按照《公司法》规定设股东会作为其权力机构
D.
合资企业合同只能约定按各方的出资比例分配利润
【单选题】John chose a dishwasher because he wanted to make dishwashers
A.
more attractive.
B.
more common.
C.
more economical.
【单选题】As a result of their experiments, Dr. Corsi's team found that______.
A.
dishwashers are very efficient machines
B.
tap water is as polluted, as bottled water
C.
indoor pollution rivals outdoor pollution
D.
gas mask is a useful protective device
【单选题】申请设立外资企业,下列选项中不属于不予批准情形的是?( )
A.
有损中国主权或者社会公共利益的
B.
危机中国国家安全的
C.
是我国国民经济发展所需的
D.
可能造成环境污染的
【单选题】John chose a dishwasher because he wanted to make dishwashers
A.
more appealing.
B.
more common.
C.
more economical.
【单选题】Could I speak to is in charge of International Sales please?
A.
who
B.
what
C.
whoever
D.
whateve
【单选题】They assured us that ______ was waiting for us they were there to share it.
A.
what
B.
whatever
C.
it
D.
whoever
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