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题文

有100g 10%的盐酸,要使其溶质质量分数增大一倍,应采用的方法是( )

A.把溶液的量倒掉一半
B.溶质的质量增大一倍
C.将100g 10%的盐酸与200g 25%的盐酸混合
D.蒸发掉溶剂的质量是原溶液质量的一半
科目 化学   题型 选择题   难度 中等
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Smiling is the best way of making friends.
When I was thirteen 46 old, my father found a job in the city. So my family moved there. I also came to a 47 school near where we live. My old school was far away. At first, I did not know anyone in my class. I was very lonely 48 I was afraid to make friends with my classmates. I 49 talk to anyone about my problem, and I didn't want my parents to 50 me.
Then one day, something good happened. I was sitting at my desk 51 as usual while my classmates were talking happily with each other. At that moment, 52 came into the classroom. I didn't know who he was. He passed me and then turned back. He looked 53 me and, without a word, smiled. Suddenly, I felt happy, lively and warm. That smile changed my life. I started to talk with the other classmates and made friends. Day by day, I became 54 to everyone in my class.
55 the smile, I have moved on to a new life. Now, I believe that the world is what you think it is. So smile at the world and it will smile back.

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