钢瓶(图1)是中空的管道，封闭的底部是凹入的，这样可以直立起来。

A cylinder (Fig. 1) is a hollow tube with a closed concave base that permits the cylinder to stand upright.

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排放板包括凹入的变形部分、形成在变形部分的中心的突起和围绕变 形部分形成的凹槽。

The vent plate includes a concave deforming portion, a protrusion formed in the center of the deforming portion, and a notch formed around the deforming portion.

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我想冒险一试，或许我们可以借助峭壁上凹入的孔穴保护，迅速通过这段糟糕的落物飞溅的地段。祈祷成功！

I want to risk it, to hurry from protected alcove to alcove, then make one mad dash through the worst of the falling projectiles-and pray.

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