我最近在Kali Linux上用apt安装R相关包（记得装的是r-base）之后，APT就出问题了。现在不管尝试安装任何包，都会弹出依赖错误，具体信息如下：

Reading package lists... Done

Building dependency tree... Done

Reading state information... Done

You might want to run 'apt --fix-broken install' to correct these.

The following packages have unmet dependencies:

apt : Depends: ubuntu-keyring but it is not installable

apt-utils : Depends: apt (= 2.2.3) but 2.0.2ubuntu0.2 is to be installed

r-cran-mgcv : Depends: r-cran-nlme (>= 3.1-64) but it is not going to be installed

r-recommended : Depends: r-cran-nlme (>= 3.1.52) but it is not going to be installed

E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

我已经尝试过这些操作，但都没用：

• 执行apt --fix-broken install和apt --fix-missing
• 手动安装缺失的包，比如尝试安装r-cran-nlme时，得到的错误信息如下：

Reading package lists... Done

Building dependency tree... Done

Reading state information... Done

You might want to run 'apt --fix-broken install' to correct these.

The following packages have unmet dependencies:

apt : Depends: ubuntu-keyring but it is not installable

apt-utils : Depends: apt (= 2.2.3) but 2.0.2ubuntu0.2 is to be installed

E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

而且不管尝试安装其他包（比如mit-scheme），都会回到最开始的那堆错误提示。

我觉得特别奇怪的是，明明用的是基于Debian的Kali，系统却一直要求安装ubuntu-keyring

附上我的sources.list内容：

# See https://www.kali.org/docs/general-use/kali-linux-sources-list-repositories/

deb http://http.kali.org/kali kali-rolling main contrib non-free

# Additional line for source packages

deb-src http://http.kali.org/kali kali-rolling main contrib non-free

有没有办法修复这些错误，让APT恢复正常工作？

UPDATE：我试了评论里提到的所有命令（update、upgrade、--fix-broken等），除了apt update会提示“签名无效”并提到公钥之外，其他命令都返回最开始的那个错误。还是搞不懂为什么基于Debian的Kali会索要Ubuntu相关的东西？

备注：内容来源于stack exchange，提问作者Salty Sodiums