Unable to correct problems, you have held broken packages问题：  sudo apt install build-essential  报错
vagrant@linux22-1:~/workspace$ sudo apt install build-essential
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
dpkg-dev : Depends: bzip2 but it is not installable
libc6-dev : Depends: libc6 (= 2.31-0ubuntu9.9) but 2.35-0ubuntu3.1 is to be installed
Depends: libc-dev-bin (= 2.31-0ubuntu9.9) but it is not going to be installed
Depends: libcrypt-dev but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
在安装软件的时候，系统崩溃了一次，不知道是否与此有关系？导致一些软件没有安全完全。
apt-cache depends build-essential 查询依赖
最后找到一篇文章，原来是镜像源的问题。
解决E: Unable to correct problems, you have held broken packages.(亲测有效)-pudn.com
如何查找镜像源连接：
清华镜像源
ubuntu | 镜像站使用帮助 | 清华大学开源软件镜像站 | Tsinghua Open Source Mirror
阿里镜像源：
ubuntu镜像_ubuntu下载地址_ubuntu安装教程-阿里巴巴开源镜像站 (aliyun.com)