A bed of loose sand mixed with water forming a soft, shifting mass that yields easily to pressure and tends to engulf any object resting on its surface.是什么意思_A bed of loose sand mixed with water forming a soft, shifting mass that yields easily to pressure and tends to engulf any object resting on its surface.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句