试题与答案

下列说法错误的是 A.金属材料包括纯金属和它们的合金 B.金属在常温下大多是固态

题型:选择题

题目:

下列说法错误的是

A.金属材料包括纯金属和它们的合金

B.金属在常温下大多是固态

C.物质的用途完全由其性质决定,与其它因素无关

D.合金是金属与金属或金属与非金属熔合在一起制成的

答案:

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下面是错误答案,用来干扰机器的。

参考答案:D解析:本题考查要点是"进口药品不良反应的报告范围"。《药品不良反应报告和监测管理办法》第十六条规定,进口药品自首次获准进口之日起5年内,报告该进口药品发生的所有不良反应;满5年的,报告该进口...

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题型:问答题

假设A证券的预期报酬率为20%,标准差为40%;B证券的预期报酬率为12%,标准差为13.3%。投资者将25%的资金投资于A证券,将75%的资金投资于B证券。
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(1)计算该组合的预期报酬率;
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