问题
选择题
设命题P：关于x的不等式a1x2+b1x+c1＞0与a2x2+b2x+c2＞0的解集相同；命题Q：
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答案
通过举反例a1=b1=c1=1，a2=b2=c2=-1，可知Q不是P的充分条件，由不等式（x-1）2+1＞0和（x-1）2+2＞0的解集都是R，即M=N=R，但不等式整理成标准形式后它们的同类项系数之比不相等．故选D．
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设命题P：关于x的不等式a1x2+b1x+c1＞0与a2x2+b2x+c2＞0的解集相同；命题Q：
|
通过举反例a1=b1=c1=1，a2=b2=c2=-1，可知Q不是P的充分条件，由不等式（x-1）2+1＞0和（x-1）2+2＞0的解集都是R，即M=N=R，但不等式整理成标准形式后它们的同类项系数之比不相等．故选D．
阅读下面短文,选择恰当的单词填空. 每词限用一次, 其中有两项多余.
Linda and Betty were both nineteen years old. In June, after a school year was over, they decided to take a vacation _小题1:___. They went to several towns and villages, visited some places of interest, saw and heard a lot of interesting things. They _小题2:___ very much. One afternoon, they were going to stay overnight in a small town. It was too __小题3:__ to go further and they wished they could find a river and swim in the cool water. They were driving the car __小题4:__ while they were looking around. Suddenly Linda saw a lake not far away. They drove there fast and _小题5:____ by the lake. They looked around and found a woman sitting on a stone and fishing there. After they ___小题6:_____ and were going to jump into the water, the woman came up to them and shouted, “Sorry, madams. Swimming __小题7:___ in the lake!” “Why didn’t you tell us about it _小题8:______ we took off our clothes?” Betty said angrily. “But it isn’t forbidden to take off clothes by the lake,” said the woman. |