He says there are about two hundred "green" charter schools across the United States.

VOA: special.2010.01.21

so, inequality between the wealthier charter schools

在较富有的特许学校和，

丰富多彩的社团活动 - SpeakingMax英语口语达人

In the United States the rules for charter schools differ from state to state.

VOA: special.2010.01.21

And now a group of charter schools have formed the Green Charter Schools Network.

VOA: special.2010.01.21

The Green Charter Schools Network holds its first national conference this October in Minnesota.

VOA: special.2010.01.21

Jim McGrath is president of the Green Charter Schools Network.

VOA: special.2010.01.21

But more than a million students attend charter schools.

VOA: special.2010.01.21