设符号[x]表示不超过x的最大整数，如[ 3 ]=1，[﹣ 2 ]=﹣2，又实数x、y满足方程组 {y=3[x]+2y=[x]+4 ，则4x﹣y的取值范围

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设符号[x]表示不超过x的最大整数，如[ 3 ]=1，[﹣ 2 ]=﹣2，又实数x、y满足方程组 {y=3[x]+2y=[x]+4 ，则4x﹣y的取值范围（）

A：﹣1，3）

B：（6，7

C：6，7）

D：9，13）

上一题下一题 0.0难度选择题更新时间:2015-03-27 03:42:10

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A

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阅读下列短文，从各题所给的A、B、C、D四个选项中，选出最佳选项。

Mr. Green's Special Speech for Students

Topic: How we can help to protect the environment

Time: 8:00—9:00 a.m. 17^th， April

Place: The school hall

Matter needing attention: Be on time

What to talk about

Our planet is in trouble! Almost every day we seem to hear about problems of the environment—pollution， climate change（气候变化）and the disappearing of the animals and the plants.

As we all know， these environmental problems are mostly caused by us humans. We must find ways to solve these problems， or the earth will no longer support human lives as always.

Each of us， whatever age we are， should do something to protect the earth. We're all responsible for the environment. What can we do? Come and listen to Mr. Green's speech tomorrow.

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