保安单元过电流防护参数：不动作电流为（），lh不动作（测试电压_爱下问搜题

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问题单项选择题

保安单元过电流防护参数：不动作电流为（），lh不动作（测试电压6OUDc，环境温度在40ºc时）。

A.50mA

B.100mA

C.200mA

D.600mA

答案

参考答案：B

阅读理解

Last Tuesday, a little girl died after eating some fried chicken. Her father bought the chicken for her from a street seller in Fenzhuang Village, Fengtai,Beijing.After testing the girl, the doctor said she was poisoned (中毒) by nitrites(亚硝酸盐). Some experts suggest that we should buy foods with QS signs. They are safer.
After hearing about the accident, many people feel more worried about the food safety because there have been many food safety problems in our country these years. For example, poisonous(有毒的) rice, oil, milk and so on have been found out recently. People feel quite afraid because these poisonous foods are rather bad for their health and even kill them. They want the government to do something to stop such poisonous foods and drinks appearing again so that they can have safe and healthy foodsand drinks.
InformationCard

小题1: The little girl died after she ate __________.

小题2:Some experts suggest that we should buy foods with __________.

小题3:Many people feel _______ about the food safety after hearing about the accident.

小题4:The poisonous foods are _________ for people's health and even kill them.

小题5:The people want __________ stop such poisonous foods and drinks appearing again.

填空题

在离心力场作用下，重介旋流器内形成不同密度的等密度线，底流、溢流悬浮液密度、加重质粒度的差异，决定了（）。