我有一个带有操作系统的Google Cloud虚拟机：
PRETTY_NAME="Debian GNU/Linux 9 (stretch)"
NAME="Debian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"
当我尝试安装R版本3.5.2无效时，我总是拥有R version 3.3.3 (2017-03-06) -- "Another Canoe"。但是，如果我尝试制作：
sudo apt purge r-base* r-recommended r-cran-*
sudo apt autoremove
sudo apt update
sudo add-apt-repository 'deb https://cloud.r-project.org/bin/linux/debian wheezy-cran3/'
deb <favourite-cran-mirror>/bin/linux/debian wheezy-cran3/
apt-key adv --keyserver keys.gnupg.net --recv-key 'E19F5F87128899B192B1A2C2AD5F960A256A04AF'
sudo apt update
sudo apt install r-base r-base-core r-recommended
输出为：
foresteyebrazil@cluster-652f-w-1:~$ sudo apt update
Ign:1 http://deb.debian.org/debian stretch InRelease
Hit:2 http://deb.debian.org/debian stretch-updates InRelease
Hit:3 http://security.debian.org stretch/updates InRelease
Hit:4 http://deb.debian.org/debian stretch-backports InRelease
Hit:5 http://deb.debian.org/debian stretch Release
Hit:6 http://packages.cloud.google.com/apt google-cloud-logging-wheezy InRelease
Hit:7 http://storage.googleapis.com/dataproc-bigtop-repo/1_3_deb9_20190426_012600-RC01 dataproc InRelease
Hit:8 http://ftp.osuosl.org/pub/mariadb/repo/10.2/debian stretch InRelease
Hit:9 http://packages.cloud.google.com/apt google-cloud-monitoring-stretch InRelease
Hit:10 http://packages.cloud.google.com/apt cloud-sdk-stretch InRelease
Ign:11 http://cran.rstudio.com/bin/linux/ubuntu stretch/ InRelease
Ign:12 http://ppa.launchpad.net/marutter/rdev/ubuntu eoan InRelease
Hit:13 http://packages.cloud.google.com/apt google-compute-engine-stretch-stable InRelease
Hit:14 http://packages.cloud.google.com/apt google-cloud-packages-archive-keyring-stretch InRelease
Err:15 http://cran.rstudio.com/bin/linux/ubuntu stretch/ Release
404 Not Found [IP: 99.84.239.73 80]
Err:17 http://ppa.launchpad.net/marutter/rdev/ubuntu eoan Release
404 Not Found
0% [Working]
在这里停止工作。有什么想法吗？谢谢