necessary protection ratio必要: requisite; necessary; certai ...保护: protect; defend; guard; safe ...率: rate; ratio; proportion保护率: protection ratio; protective rate射频保护率: radio frequency protection ratio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:必要保护率,即可在微信中查询翻译