问题
选择题
在电场中某点放一检验电荷，其电荷量为q，受到的力为F，该点电场强度为E。下列说法正确的是[ ]
A．若移去检验电荷，该点电场强度变为零
B．若该点放一电荷量为2q的检验电荷，则该点场强变为
E
C．该点放一电荷量为2q的检验电荷，该点场强仍为E
D．该点放一电荷量为2q的检验电荷，该点场强为2E
答案
答案：C
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在电场中某点放一检验电荷，其电荷量为q，受到的力为F，该点电场强度为E。下列说法正确的是[ ]
A．若移去检验电荷，该点电场强度变为零
B．若该点放一电荷量为2q的检验电荷，则该点场强变为E
C．该点放一电荷量为2q的检验电荷，该点场强仍为E
D．该点放一电荷量为2q的检验电荷，该点场强为2E
答案：C
Time flies so quickly! We become mature (成熟的 ) girls or boys, or at least we we are. At the same time, our parents are no longer young. They all they have to us but never look forward to getting back. When we are ill in bed, it is our parents who look us day and night; when we are trying to make , it is our parents who are much happier than we are; when we're hungry or cold or sad, it is our parents who give us help. But what have we done for our parents? we grow up, we have our own ideas and we think we are enough to think and act by ourselves, so we usually dislike their care. , sometimes we don't listen to them; even with them ! To change the , we must act at once, letting them know that we love them, too. In doing so, don't hesitate(犹豫) and don't be .Try our best to understand our parents, something for our parents and not to make them feel hopeless. In a word, make it a duty to bring to our parents, for that's the very sign that we are really mature. Children are parents’ and we are carrying both our dreams and theirs. The pleasure of our parents is what we should try to do!
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