3~60kV系统,中性点不直接接地,在发生单相接地故障后,仍能允许带负荷( )。

题型:单项选择题

问题:

3~60kV系统,中性点不直接接地,在发生单相接地故障后,仍能允许带负荷( )。

A.0.5h;
B.1h;
C.2h;
D.1.5ha

考点:注册电气工程师发输变电专业电气主接线
题型:单项选择题

两个相同的金属小球所带电量不同,小球间相距一定距离时有相互作用的库仑力。如果将它们相互接触一下,再放到原来的位置,则两金属小球之间库仑力的变化情况是:

A.如果相互接触前库仑力是引力,则相互接触后库仑力仍是引力

B.如果相互接触前库仑力是引力,则相互接触后库仑力是斥力

C.如果相互接触前库仑力是斥力,则相互接触后库仑力一定增大

D.如果相互接触前库仑力是斥力,则相互接触后库仑力一定减小

题型:单项选择题

阅读短文,根据文章的内容填词,每空一词。

Lucy and Ann are good friends. They are from different countries. They are now in China. They are both in Class 3. Lucy is twelve, but Ann is eleven. Lucy is from the USA. She arrived in China 3 years ago. And Ann is from English. She is in China for two months. They both speak English. Lucy usually goes to school on foot. Ann usually goes to school by subway. Mr. Yang is their Chinese teacher. Lucy is good at Chinese. But Ann can only speak a little Chinese. Mr. Yang and Lucy often helps her study Chinese.

小题1:Lucy and Ann are in the ­­_____ class, but they come ­­from _________ countries.

小题2:Lucy ________ in China _________ three years.

小题3:Lucy usually _________ to school and Ann _______ the subway to school.

小题4:Lucy _______ _______ in Chinese.

小题5:Lucy often helps Ann ________ _________ Chinese.

题型:单项选择题

细胞内含量最多的RNA是()

A.snRNA

B.snoRNA

C.tRNA

D.rRNA

题型:单项选择题

抽屉试验时小腿上端向前滑动提示()

A.胫侧副韧带撕裂

B.腓侧副韧带撕裂

C.前交叉韧带损伤

D.后交叉韧带损伤

E.髌韧带损伤

题型:单项选择题

氯碱厂有哪些化学有害因素其接触限值各是多少?

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