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【单选题】
在光电效实验中，影响准确确定光电管的截止电压的主要因素有二：1，当光照射到阴极时，必然有部分光漫反射至阳极，至使阳极产生光电效应并发射光电子，这些光电子很易到达阴极而形成（）；2，当光电管无任何光照时，在外加电压作用下仍会有微弱电流流过，我们称之为光电管的（）。A.
暗电流；反向电流
B.
暗电流；光电流
C.
反向电流；暗电流
D.
反向电流；光电流
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【单选题】某君到一百货商店考察,随手翻阅了其规章制度手册,有三条特别引起他的注意: ——“我们只售高贵时髦的衣服和各种高级用具。” ——“货物售出超过 30 天,不再退还购货款。” ——“在退还顾客购货款前,营业员需注意检查退回的货物,然后取得楼层经理的批准。” 试问这三条规定各自是属于常用计划的哪一种形式?()
A.
都是规则
B.
都是政策
C.
分别是政策、程序、规则
D.
分别是政策、规则、程序
【单选题】Not only the sailors but also the captain of the ship _____ frightened during that voyage.
A.
has
B.
have
C.
was
D.
were
【单选题】In the opinion of many Americans and Europeans, we only began to really explore our world in the sixteenth century. According to them, the sailors of the ancient world did not explore distant parts of...
A.
According to the writer, we only began to really explore the world in the sixteenth century.
B.
In the history of science, people sometimes have to discover a fact a second time.
C.
The ancient Egyptians had very little knowledge about the stars.
D.
The writer agrees with many Americans and Europeans except for the two facts mentioned in the passage.
【单选题】某君到一百货商店考察,随手翻阅了其规章制度手册,有三条特别引起他的注意:“我们只售高贵时髦的衣服和各种高级用具”;“货物售出超过30天,不再退还购货款”;“在退还顾客购货款前,营业员需注意检查退回的货物,然后取得楼层经理的批准”。试问这三条规定在计划表现形式中各归为( )。
A.
政策、程序、规则
B.
政策、规则、程序
C.
都是规则
D.
规则、政策、程序
【简答题】正弦交流电网电压值，如380V，220V，指的是（ ）。
【单选题】Why does the author mention Japanese Ministry of International Trade and Industry?
A.
To make a comparison between the practices of nationalization in America and Japan.
B.
To show that America is violating the spirit it has preached for long.
C.
To show that Japanese enjoys an industrial development because of its nationalization.
D.
To criticize America for its inadequacy in innovation.
【单选题】Not only sailors but also the captain of the ship _______ frightened during that voyage.
A.
has
B.
have
C.
was
D.
were
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