由於安裝的Ubuntu LTS是英文版的，軟體源就預設都是 us.archive.ubuntu.com（英國） 的，所以很慢

為了提高下載速度，將源改為國內的 cn.archive.ubuntu.com ，現在 cn.archive.ubuntu.com 指向阿里雲的開源映象站 mirrors.aliyun.com，下載速度很快。

ubuntu 18.04(bionic) 配置如下:

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
 


deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
 


deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
 

在ubuntu下執行命令sudo mv /etc/apt/sources.list /etc/apt/sources.list_backup將sources.list 檔案備份

執行sudo vi /etc/apt/sources.list編輯sources.list 檔案，有內容則將檔案內容清空，並貼上上面的內容，儲存退出

執行sudo apt-get update更新apt軟體源

完畢。