传声筒

例句：

1. 1. The teacher used a megaphone to make sure everyone heard the announcement.
   老师用麦克风确保每个人都能听到公告。
2. 2. The speaker at the conference used a microphone to transmit their message.
   会议的发言人使用麦克风来传输他们的消息。
3. 3. The engineer used a microphone to record the sound of the engine.
   工程师使用麦克风记录发动机的声音。