根据汉语意思完成句子，每空一词。

如图所示，电源电压保持不变，闭合开关S，下列说法正确的是（  ）

阅读短文，根据要求完成下面各小题。
       Too many people want others to be their friends, but they don't give friendship back. This is why some friendships don't last long .To have a friend, you must learn to be a good friend. Learning to be a good friend means learning three rules: be honest; be generous; be understanding.
        Honesty is where good friendship starts. Friends must be able to trust(信任)one another. They should tell the truth. If you aren't honest, you'll lose your friend's trust. (1)A study shows that those who often tell lies can't get on well with the other people. Good friends always depend on one to speak and act honestly.
       Generosity makes a friendship grow well. It means sharing. You do not have to give your lunch money or your clothes. Naturally you want to share your ideas and feelings. These can be very valuable to a friend. They tell your friend what is important to you. By sharing them, you help your friend know better.
      Sooner or later everyone needs understanding and help with a problem. Something may go wrong at school. Talking about the problem can make it easier to solve. Turning to a friend can be a first step in solving the problem. So to be a friend, you must listen and understand．(2)Try to put yourself in your friend’s place, or you can't understand the problem better.
      Now, do you know what you should do if you want to be a good friend and keep your friends?