## ubuntu20 ``` deb http://mirrors.aliyun.com/ubuntu/ focal main restricted deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted deb http://mirrors.aliyun.com/ubuntu/ focal universe deb http://mirrors.aliyun.com/ubuntu/ focal-updates universe deb http://mirrors.aliyun.com/ubuntu/ focal multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-updates multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted deb http://mirrors.aliyun.com/ubuntu/ focal-security universe deb http://mirrors.aliyun.com/ubuntu/ focal-security multiverse ```