standard practice for selection of valve operators阀门: valve; tap操作: operate; manipulate; handle器: implement; utensil; ware的: 4次方是 The fourth power of 2 i ...选择: pick and choose; select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:阀门操作器的选择，即可在微信中查询翻译
