In all three of America's biggest cities, murder rates have fallen to their lowest levels since the nineteen sixties.

在所有美国三个最大城市中，凶杀案的比率已经降到上世纪六十年代以来的最低点。

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A rocket launch countdown. A common sound in the nineteen sixties. But this was not just another launch. It was the beginning of a historic event.

火箭发射倒计时，一个在二十世纪六十年代广为人知的声音，而这并不只是一次普通发射，而是一个具有历史意义的事件的开始。

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He did so after witnessing the popularity of the activity himself during a trip to New Zealand in the nineteen sixties.

VOA: special.2011.06.28

In the nineteen sixties, Ray Davis Junior used the mine for his work showing the existence of solar neutrinos.

VOA: special.2009.07.21

Its large rooms and affordable rent gave middle class black people a new kind of housing opportunity in the nineteen sixties.

VOA: special.2009.12.27

Then came the great expansion of the nineteen-sixties, when the baby boomers entered and enrollments doubled.

NEWYORKER: Live and Learn

The early nineteen-sixties were a turbulent time in American politics, for the right wing in particular.

NEWYORKER: Confounding Fathers

It was Budyko, in the nineteen-sixties, who first suggested cooling the earth by putting sulfur particles in the sky.

NEWYORKER: The Climate Fixers