The reasons why there is no sound when the video is imported into AE are as follows:

1. The video and audio files are damaged. The easiest way to check whether the video audio is damaged is to open the video with playing software to see if there is sound.

2. The brain is silent. Check whether the computer speaker is turned on, and if it is, turn it on.

3. AE turned on the mute. Check whether the icon's logo is mute, and if it is, just turn it on.

4. The preview mode is wrong. You can't hear the sound when previewing with the space bar. You need to press "" on the keypad to preview the sound. If it is a notebook, press "fn+Num Lk" and then press "m" to preview. Or press the icon to preview.

5. Audio output is not checked. Remember to check the audio output option.