问题
选择题
浓度为p%的盐水m公斤与浓度为q%的盐水n公斤混合后的溶液浓度是（ ）
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答案
∵浓度为p%的盐水m公斤中含盐p%m，浓度为q%的盐水n公斤中含盐q%n，
∴混合后溶液的浓度为
，p%m+q%n m+n
故选D．
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浓度为p%的盐水m公斤与浓度为q%的盐水n公斤混合后的溶液浓度是（ ）
|
∵浓度为p%的盐水m公斤中含盐p%m，浓度为q%的盐水n公斤中含盐q%n，
∴混合后溶液的浓度为
，p%m+q%n m+n
故选D．
| 完形填空。 | ||||
| Mr Chen is a farmer who 1 in western China with his wife and two sons. One year ago, he discovered that he had cancer. The doctor told him that he needed 2 at once. And he said the operation would 3 thousands of yuan. It was too much money for Mr Chen and his wife. They had no job and 4 were at school. The situation seemed 5 . Two weeks later, however, Mr Chen got some 6 news. He was told about a health care project which provides medical treatment for poor patients in 7 China. They 8 to pay only half the cost or even less. Thanks to the project and the kindness of 9 family and neighbours, he was able to receive an operation just 10 to prevent the illness from getting worse. 11 he has returned to his family. The 12 of this health care project is to improve the situation for poor people in western China. So far, the project has helped more than 5,000 people 13 medical aid. The Chinese government is 14 working together with other countries and international organizations to do this. They hope to develop a new health care model 15 China. As our country develops, we must remember the responsibilities (责任) of caring for the weakest members. | ||||
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