manual gain control

例句：

1. 1.The manual gain control on this camera is very user-friendly.
   这款相机的手动增益控制非常用户友好。
2. 2. The engineer used the manual gain control to adjust the sensitivity of the camera.
   工程师使用手动增益控制来调整相机的灵敏度。
3. 3. During the testing process, we need to manually set the gain control to ensure the accuracy of the results.
   在测试过程中，我们需要手动设置增益控制以确保结果的准确性。