R-f preselectors
[电] 射频预选器
🗣️ 情景例句
When did the Roman Empire come into being?
罗马帝国是什么时候形成的？
His heart cannot be pure whose tongue is not clear.
嘴不净者心不纯。
What happened on the march then?
那么 ，在游行中发生了什么事？