They count down the final seconds to midnight as they watch a brightly lit ball slide down a pole on top of a tall building.

VOA: special.2009.12.28

It's not going to be a backscatter event if your ping-pong ball hits the frame or these strings, or the top part.

打到原子核了就是背散射,如果打到框上。

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You have a tube, a transparent--a tube--a hollow tube, and at the top of the tube you throw a ball through so it whips through the tube and it comes out.

用一根管子,一根透明中空的管子,从管子最上面,你丢进去一个小球,小球迅速穿过管子,飞出来

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