ht@ubuntu:/etc/apt$ sudo apt-get update
Hit:1 http://mirrors.tuna.tsinghua.edu.cn/mariadb/repo/10.4/ubuntu bionic InRelease
Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]
Hit:3 http://us.archive.ubuntu.com/ubuntu bionic InRelease
Get:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Err:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease
Connection timed out [IP: 91.189.91.26 80]
Get:5 http://us.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]
Fetched 148 kB in 1min 2s (2,394 B/s)
Reading package lists... Done
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease Connection timed out [IP: 91.189.91.26 80]
W: Some index files failed to download. They have been ignored, or old ones used instead.