Why can't a violist play with a knife in his back?

为什么中提琴手演奏时背后不能放把刀？

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His father first tried to explain not to play with knife but obviously a kid is a kid, he won't listen.

他的父亲首先尝试跟他解释说不要玩刀，但孩子就是孩子，根本不听。

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A little kid held a knife and insisted his father to play with it.

一个小孩拿着一把刀，坚持要他父亲和他一起玩。

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Few psychotherapists want to take on patients who kick in walls, play Russian roulette with a loaded gun, slice up their arms with a knife, or end up in the intensive care unit twice in one month from suicide attempts.

FORBES: The Woman Who Stops Patients From Killing Themselves