By varying the groove spacing, the diameter of the single or double diameter hole, and the rear air cavity depth and content, one can obtain absorption over a wide variety of frequencies.

通过改变槽间距，直径的单人或双人直径孔，与后方空气腔的深度和内容，就可以得到吸收超过各种各样的频率。

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Sights were fixed, pre-adjusted for 100 yards distance, peep hole rear and blade front.

景点是固定的，预先为100码的距离，窥视孔后方和刀片前调整。

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The top part of one inner bolt which matches the blank hole channel of the outer hollow screw is also conical. The rear is provided with a thread and a tetragonal body for holding.

一与外空心螺钉的盲孔道相匹配的内螺栓，内螺栓的尖端部位亦为锥形，尾部设有螺纹和供握持用的四方体。

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Survivors told how they clung on bags, ropes and nettings for almost two hours to stop themselves also being dragged through the rear hole.

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The 28-year-old woman, who works at Mains of Taymouth, stumbled into the hole as she took a shortcut across ground at the rear of the caravan park at about 01:30.

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