问题
选择题
一种浓度是15%的溶液30千克，现要用浓度更高的同种溶液50千克和它混合，使混合后的浓度大于20%，而小于35%，则所用溶液浓度x的取值范围是[ ]
A.15%<x<23%
B.15%<x<35%
C.23%<x<47%
D.23%<x<50%
答案
答案：C
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一种浓度是15%的溶液30千克，现要用浓度更高的同种溶液50千克和它混合，使混合后的浓度大于20%，而小于35%，则所用溶液浓度x的取值范围是[ ]
A.15%<x<23%
B.15%<x<35%
C.23%<x<47%
D.23%<x<50%
答案：C
For each blank in the following passage there are four words or phrases marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context. My friend had mentioned that her father had a lot of children’s toys that he was looking to give away. She knew I had a three-year-old daughter so she thought of me first. I told her I would 36 it if I could get some nice things for my daughter, which I wouldn’t otherwise have been able to 37 . When I met her father, he began to explain that he was 38 once too and that he would hate to 39 things that could be very 40 . At first, he thought of taking everything to the Salvation Army but then he 41 to see if anyone he knew could use them first. When he was 42 me around, I saw a bed, a slide(滑板)，a kitchen set and many other things that made me surprised. As my eyes were wide and beginning to tear up a bit, he told me not to feel guilty. He said I was 43 him by getting rid of them. As I was looking around, I did feel guilty, but I tried to remain more grateful than guilty because he told me to. Every time I tried to 44 him for giving my daughter all these 45 things, he would thank me right back and was grateful that these toys would be put to good use. So, sometimes when we are helped by others, the others that helped us are helped as a side –effect. In the 46 of charity , it makes sense to feel grateful, but guilt is just as normal, I know we could have lived without a slide, which is why I do feel guilty, but I am grateful all the same because my daughter 47 enjoys all these nice things!
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