freeadj.自由的；免费的；畅通的；没有…的；未使用的；空闲的；随意的v.释放；使自由；使摆脱；解除；使可用于(某目的)adv.免费地；自由地free walk自由慢步

1. Synchronous FM System provides broadcasters with continuous program coverage along highways or within a region under-served by a single FM signal.
   摘要调频同步广播系统是仅使用一个频率，实现地域覆盖或高速路线性覆盖的调频传输系统。