reactionless servo-mechanism无: not have; there is not; be w ...反作用: reaction的: 4次方是 The fourth power of 2 i ...伺服: servo机构: mechanism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:无反作用的伺服机构，即可在微信中查询翻译
