Audio can not be heard if resolution is increased

[7z-775]

I am using youtube-dl and I have saved retro movies(https://www.youtube.com/watch?v=WUgmlmuHZ9c).
However, if you raise the resolution, the sound of the movie will be lost or you will be unable to read it.
What is the cause of this?

=Debug Log=

function@linux-eplz:~>youtube-dl -v -f 135 https://www.youtube.com/watch?v=WUgmlmuHZ9c
[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'-v', u'-f', u'135', u'https://www.youtube.com/watch?v=WUgmlmuHZ9c']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2018.01.27
[debug] Python version 2.7.13 (CPython) - Linux-4.4.104-39-default-x86_64-with-SuSE-42.3-x86_64
[debug] exe versions: ffmpeg 3.3.4, ffprobe 3.3.4
[debug] Proxy map: {}
[youtube] WUgmlmuHZ9c: Downloading webpage
[youtube] WUgmlmuHZ9c: Downloading video info webpage
[youtube] WUgmlmuHZ9c: Extracting video information
[debug] Invoking downloader on u'https://r6---sn-3v2upjvh-3pm6.googlevideo.com/videoplayback?ms=au%2Crdu&clen=10443042&mv=m&mt=1517481577&expire=1517503298&requiressl=yes&ei=4u5yWuGPE4GSgQPJuIrABA&ipbits=0&mn=sn-3v2upjvh-3pm6%2Csn-3pm76n7r&keepalive=yes&mm=31%2C29&id=o-AMzPYQ0rYaRmBEKyjLXdTg5_u98-qdM69URm1rHAV4oA&itag=135&ip=121.84.70.156&key=yt6&dur=159.168&lmt=1394801149544973&aitags=133%2C134%2C135%2C160%2C242%2C243%2C244%2C278&mime=video%2Fmp4&fvip=6&sparams=aitags%2Cclen%2Cdur%2Cei%2Cgir%2Cid%2Cinitcwndbps%2Cip%2Cipbits%2Citag%2Ckeepalive%2Clmt%2Cmime%2Cmm%2Cmn%2Cms%2Cmv%2Cpl%2Crequiressl%2Csource%2Cexpire&gir=yes&initcwndbps=1611250&signature=843AAE6C638099AD59700D400D638700BD5ABAC9.6094D7C0160BAF03630A2612B10946BC39A12E4D&pl=18&source=youtube&ratebypass=yes'
[download] Destination: BBC Micro with 32016 Second Processor booting PanOS-WUgmlmuHZ9c.mp4
[download] 100% of 9.96MiB in 01:05

The problem is occurring on smartphone, PC.

I write in Translate-shell because I have poor English grades.
sorry

[s104346]

Your selected format (-f 135) only contains a video stream without any audio.

$ youtube-dl -F https://www.youtube.com/watch?v=WUgmlmuHZ9c
...
135          mp4        640x480    480p  573k , avc1.4d401e, 30fps, video only, 9.96MiB
...

You need to merge it with an available audio-only format:
youtube-dl -f 135+140 https://www.youtube.com/watch?v=WUgmlmuHZ9c