Cup: The cup should be "u" shaped and resemble a bowl or rounding bottom. A "v" shaped bottom would be considered too sharp of a reversal to qualify.

要点二：u型是重要的形态标志，看起来像个碗，一般认为V型则反转太剧烈了，。

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Caption: the cloud patterns seen in this image resemble the V-shaped wake left by objects moving through water.

描述：图片中云的形态有点像物体划过水面时留下的V形尾迹。

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