题干

如图所示,空间分布着竖直向上的匀强电场E,现在电场区域内某点O处放置一负点电荷Q,并在以O点为球心的球面上选取a、b、c、d四点,其中ac连线为球的水平大圆直径,bd连线与电场方向平行.不计空气阻力,则下列说法中正确的是(   )

A:b、d两点的电场强度大小相等,电势相等

B:a、c两点的电场强度大小相等,电势相等

C:若从a点抛出一带正电小球,小球可能沿a、c所在圆周作匀速圆周运动

D:若从a点抛出一带负电小球,小球可能沿b、d所在圆周作匀速圆周运动

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B,C

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    Getting your children to study can be a little like getting them to eat their vegetables. ____ Make a study time and have it at the same time every day. This will help your kids to learn to schedule their day and will give them a sense of control over how they spend their time.

    Allow them to study in blocks of time,such as for half an hour with a five-minute break in the middle. ____ Ideal(理想的) study times are after dinner or right after school before dinner.

    Never allow your children to study in front of the television,as that will encourage passive activity. ____ You'll also need to help your kids find the right place to study. After you've set up a good study time for little learners,set up a good place where they can get those creative juices flowing. ____ Make sure there is a table or a desk and a comfortable chair.

    ____ This includes helping them out with their homework sometimes and being there for them with the answers to any questions. The input you give your children during study periods will help form a bond and help make studying enjoyable.

A.Pick a place where your children can study properly.B.Hold them to the schedule they create for themselves.

C.Finally,spend time with your kids when they're studying.

D.Keep the atmosphere light and offer lots of encouragement,too.

E.Instead,use TV as a treat or a reward when the homework is completed.

F.Try to stop this bad habit by offering some sort of reward.

G.One of the best ways to form good study habits for your kids is to design a schedule that they keep to.