An acoustically absorbent material (e. g. a fabric) may be secured to an inwardly facing surface of any part formed from perforated sheet metal.

吸音材料(例如织物)可固定至由穿孔金属板形成的任何部分的面向内的表面。

youdao

You can move the handset (and its front-facing camera) up and down as it speeds along any flat surface, responding to commands from someone on the other end of a Skype video chat.

ENGADGET: Insert Coin: Botiful telepresence robot for Android (video)