如图为一条电场线，可以判定（ ）
A．该电场一定是匀强电场
B．A点电势一定低于B点电势
C．负电荷放在B点的电势能比放在A点大
D．负电荷放在B点的电势能比放在A点小
A、由于只有一条电场线，不能判断电场线的疏密情况，也就不能判断电场强度的情况，所以A错误；
B、根据沿电场线的方向，电势降低，可以知道，A点电势一定高于B点电势，所以B错误；
C、负电荷从A运动到B的过程中，电场力做负功，电荷的电势能增加，所以负电荷放在B点的电势能比放在A点大，所以C正确，D错误；
故选C．
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| One day, Tom was on his way home. When he passed a corner, he heard a weak(微弱lyj) cry. Tom stopped 1 and looked around. At last he found a little 2 . It was thin and dirty. Its cry sounded 3 .Tom went to it,“Come on! I'll take you 4 ” Tom's mother didn't like animals. She said to Tom, "You know, your father 5 dogs. We can't keep the dog with us. What about giving it to a person who likes dogs? Then it will 6 a home." Tom said, "OK! But can we keep it for some time 7 giving it to others?" His mother said, "Of course, but you must look after it yourself. " So every day after Tom got home from school, he gave the dog some 8 and then cleaned it. One month later,they were all surprised to 9 the dog was so white with long hair and it looked 10 ! Tom and his parents liked it very much,and they didn't want to give it to others. Now Tom's family lived a happy life with the dog. | ||||
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