automatic carriage自动: voluntarily; of one's own ac ...滚轮: contact roller; trolley whee ...从动滚轮: return idler活动滚轮: action roller移动滚轮: shifting roller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:自动滚轮，即可在微信中查询翻译
