If you imagine yourself tossing a ball in the air in front of a mirror, P symmetry seems intuitively obvious.

想像如果你在镜子前面丢球，P对称看来是无庸置疑的。

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Steele, K. M. , T. N. Ball, and R. Runk, " Listening to Mozart does not enhance backwards digit span performance. " Percept Mot Skills, 1997. 84 (3 Pt 2): p. 1179-84.

听莫札特的音乐并不会增强在数字回朔测验中的表现〉 《知觉技能与运动技能》，1997。84 （第3册第2部分）：1179-84页。

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P: Turn & slip indicator ball stuck in center during turns.

在转弯过程中，转弯侧滑仪小球保持在中间不动。

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The raising of the ball starts at 6:05 p.m.

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At 8 p.m. on the dot, he gets to play indoor ball.

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Lady Gaga performed in Times Square on Saturday night and she was the mayor's special guest, helping him push the Waterford crystal button at 11:59 p.m. that signals the descent of the New Year's Eve ball.

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