根据短文内容回答问题。

    More and more children play computer games for a long time. Most parents feel quite worried about that. But in fact, not all games are bad for kids.

    There is a popular game called Mole Manor（摩尔庄园）on line now. In this game, it is a world of the kids. Children can do what they want to do there. They can buy what they want and even the pets. Almost every player has one or two pets called Lam. The players can buy something for Lam and they also want to give them some food to eat. Sometimes kids must wash their pets to keep them clean. At that time, they are the parents themselves. That helps them know how much their parents do for them. There are many other games for kids in Mole Manor. Kids can be a policeman here. They can also be a teacher to help the Lams to learn more.

    Get the kids to play for only half an hour on line. Don't hate all computer games and you can be a good parent.

图中小明蹬着滑板车滑行，根据所学知识，请回答下列问题：

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某欧姆表的内部结构如图甲所示电路，欧姆表开关拨至“ ”，并进行了必要的调零。一同学准备用一个电阻箱R_x较精确地测出欧姆表的电源的电动势E和该倍率下完成调零后欧姆表的内阻 ，他的操作步骤是：

a．将欧姆表与电阻箱R_x连成图甲所示的闭合电路；

b．调节电阻箱阻值，记下电阻箱示数R_x和与之对应的电流表G的示数I；

c．将记录的各组R_x、I的数据描点在图乙中，得到 图象；

d．根据图乙作得 的图象，求出电源的电动势E和欧姆表内阻R_内。