所以我有一个漂亮的系统运行得非常好，直到我昨晚想设置一个旧的网络摄像头。我做了 sudo apt-get update 并得到了这个：
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W: The repository 'http://security.ubuntu.com/ubuntu yakkety-security Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'http://ca.archive.ubuntu.com/ubuntu yakkety Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore …