test microphone

例句：

1. 1. The engineer tested the microphone before recording the sound.
   工程师在录音之前测试了麦克风。
2. 2.The teacher asked the students to test their microphones at the beginning of class.
   老师要求学生们在课开始时测试他们的麦克风。
3. 3. The technician used a test microphone to check the quality of the recording.
   技术人员使用测试麦克风检查录音的质量。