ring extension环: ring; hoop扩张: expand; enlarge; spread循环扩张: cyclic extension循环扩张域: cyclic extension field活塞环扩张器: compression inner ring下载手机词典可随时随地查词查翻译关注微信公众号:chachacidian,回复:环扩张,即可在微信中查询翻译