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【单选题】
镭是元素周期表中第ⅡA族元素，下列关于镭的叙述不正确的是A.
镭比钙的金属性更强
B.
在化合物中呈+2价
C.
镭是一种放射性元素
D.
氢氧化镭呈两性
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举一反三
【单选题】我国用电规程中规定，在电压低于1000V的中性点接地的三相四线制供电系统中，例如380V/220V系统不允许采用（），只能采用（）。
A.
保护接零；保护接地
B.
保护接地；重复接地
C.
保护接地；保护接零
D.
保护接零；重复接地
【单选题】Would you risk your life for a country that considered you a second-class citizen?Would you join a military that asked you to risk sacrificing your life but separated you from other soldiers because o...
A.
American Soldiers in World War II.
B.
American Civil Rights Movement.
C.
The Tuskegee Airmen.
D.
Racial Discrimination in the U. S.
【单选题】How do I like to travel? Many people like to travel by plane, but I don’t like it because an airport is usually far from the city. You have to get there early and wait for hours for the plane to take ...
A.
he thinks it takes a lot of time to go to and get out of the airport.
B.
He likes to take a train because it takes a little more time.
C.
He likes to take a car because he has a car.
D.
none of them
【单选题】在去北京的旅途中,为了保证财物安全,特意带了密码锁,密码锁有3个拨号盘。每个拨号盘上有从0到9共10个数字,这3个拨号盘可以组成不同的三位数字密码的个数是多少? ( )
A.
27
B.
30
C.
720
D.
1000
【单选题】听力原文：M: Lucy, if you are going to Naomi' s party tomorrow night, could you pick me up? My car's at the garage until this weekend. W: No problem, Jerry. What time should I pick you up? M: Let' s see. I...
A.
In a parking area
B.
In a repair shop
C.
At Lucy' s house
D.
At the man' s house
【单选题】----Woul d you mind the windwow? ---- It’s cold outside.
A.
me open ,Of course not
B.
mine opening , Certainly not
C.
my opening , You’d better not
D.
mine open , Not at all
【多选题】下面关于中性点接地方式使用一般原则叙述正确的是（）。
A.
中性点直接接地方式使用在电压等级在110kV及以上电压的系统和380V／220V的低压配电系统中
B.
中性点不接地方式使用在单相接地电容电流分别不超过30A的10kV系统和不超过10A的35kV系统
C.
中性点经消弧线圈接地方式使用在单相接地电容电流分别超过30A的10kV系统和超过10A的35kV系统
D.
中性点经消弧线圈接地方式用于雷电活动强、供电可靠性要求高的110kV系统
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