执行以下步骤:
# sudo CP/etc/apt/sources.list/home/sources.list.bk备份#删除sudorm-RF/etc/apt/sources.list #写入vist #
#默认情况下,为了加快apt update的速度,会注释源代码镜像。 如有必要,请参阅deb https://mirrors.tuna.Tsinghua.edu.cn/Ubuntu/focalmainrestricteduniversemultiverse # de B-src 3359 mirrors.ce focalmainrestricteduniversemultiversedeb https://mirrors.tuna.Tsinghua.edu.cn/Ubuntu/focal-updatesmainrestrictes de B Ubuntu/focal-updatesmainrestricteduniversemultiversedeb 3359 mirrors.EB 3359 focal-backportsmainrestricteduniversemultemultiveriveb de B-src https://mirrors.tuna.Tsinghua.edu.cn/Ubuntu/focal-backportsmainrestricteduniversemultiversedeb 33https://mirors focal-securitymainrecority de B-src https://mirrors.tuna.Tsinghua.edu.cn/Ubuntu/focal-securitymainrestricteduniversversersteduniveversiverated 启用deb https://mirrors.tuna.Tsinghua.edu.cn/Ubuntu/focal-proposedmainrestricteduniversemultiverse # de B-src 3359
sudo apt-get update已将软件源代码切换为清华源代码。