One of a series of small ridges or grooves on the surface or edge of a metal object,such as a thumbscrew,to aid in gripping.是什么意思_One of a series of small ridges or grooves on the surface or edge of a metal object,such as a thumbscrew,to aid in gripping.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句