For a time, elementary school was the answer to the question of how to build a broad middle class in America. And for a time after that, the answer was high school.

在一个时间段内，构建美国中产阶级阶层的答案来自初中毕业生，此后一个时间段，就是高中毕业生。

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Postal Service stamp - one of the so-called "forever stamps" that will be good for first-class postage no matter how high rates go in the future.

这种邮票是“永久邮票”之一，也就是无论将来利率多高，它都会被用作头等邮资。

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Each classroom is equipped with high-resolution camera, and it is quite convenient that parents can observe how the class is going of their children during the class time.

每间教室配有高清晰度摄像头，方便家长及班主任随时观察学员上课表现情况。

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But a spat about how important readability is to high-class fiction - as the Booker chair Stella Remington discovered last year - will do.

BBC: A Point Of View: And prizes for all

Esther Peterson, the top-ranking woman in the Kennedy administration, asked an auditorium full of working-class high school girls in Los Angeles how many expected to have a "home and kids and a family, " and the room was full of waving hands.

NPR: Excerpt: 'When Everything Changed'

New markets seldom get built this way, unless the consumer experience is so compelling and the brand so powerful that people will consider a totally new class of product (see the iPad, which demonstrates just how high a bar those criteria are to meet).

FORBES: Is Google Too Rushed to Pioneer?