一项工作，A，B两人合作完成工作的
需要6天，已知A完成全部工作的
与B完成全部工作的
所用时间相同，那么甲、乙单独完成这项工作各需要多少天().
A.12，15
B.15，12
C.18，12
D.18，15
E.20，12
参考答案：C
解析：
效率问题．
设tA，tB分别表示A，B两人单独完成工作所需时间，验证选项，只有C满足
[评注] 可以通过验证选项的思路来降低列方程计算的难度．
| 完形填空 | ||||
| Do you like traveling by train? 1 do you like to do when you are traveling by train? When traveling 2 train, some people like to read, some people like to talk and some others 3 like to sleep. Many people think train trips are boring, 4 I enjoy it very much.I usually like to look out of the 5 when I travel on the train. There are many 6 things along the railway-the mountains, the rivers, the houses,the animals on the farms and… I often feel that life is a 7 time when I'm on the train. The train runs so fast and the things out ofthe window go away 8 .Travel is short.Whether you aretraveling by train, by plane 9 by bus, it should be fun. Life is short, 10 .Value（珍视）it and live a happy life. | ||||
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