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圆珠笔摇摇摆摆地直立在笔架前面不倒下,你感到奇怪吗?这是在表演魔术?不!这其实是磁力的作用造成的。
Is it strange that the ball-point pen wobbles upright in front of the carriage, is it performing magic? No! This is actually caused by the effect of magnetism.