deb https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic main main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse

# deb https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-proposed main restricted universe multiverse
# deb-src https://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-proposed main restricted universe multiverse