此应用程序支持的C#linux mono运行时版本不可用

关于这个话题，我见过其他的问题，但对我来说是不同的

这是我的场景（在ubuntu上）

在mono目录中我得到了这个

airone@airone:/usr/lib/mono$ ls -l
totale 148
drwxr-xr-x   2 root root  4096 dic  7 13:44 2.0
drwxr-xr-x   2 root root 20480 dic 13 01:24 2.0-api
drwxr-xr-x   2 root root  4096 dic 13 01:24 3.5-api
drwxr-xr-x   2 root root 12288 dic 13 01:24 4.0
drwxr-xr-x   2 root root 20480 dic 13 01:24 4.0-api
drwxr-xr-x   4 root root 20480 dic 13 01:27 4.5
drwxr-xr-x   3 root root 24576 dic 13 01:24 4.5-api
drwxr-xr-x   3 root root  4096 dic  7 13:44 aot-cache
drwxr-xr-x   2 root root  4096 dic  7 13:42 compat-2.0
drwxr-xr-x 234 root root 12288 dic  7 13:49 gac
drwxr-xr-x   2 root root  4096 dic 13 01:24 lldb
drwxr-xr-x   3 root root  4096 dic  7 13:44 mono-configuration-crypto
drwxr-xr-x   2 root root  4096 dic 13 01:27 monodoc
drwxr-xr-x   5 root root  4096 dic  7 13:42 xbuild
drwxr-xr-x   4 root root  4096 dic  7 13:42 xbuild-frameworks
airone@airone:/usr/lib/mono$ 

在4.5中有一个文件

airone@airone:/usr/lib/mono/4.5$ ls -l | grep msco
-rw-r--r-- 1 root root 1525760 dic 13 01:46 mscorlib.dll
airone@airone:/usr/lib/mono/4.5$ 

这让我发疯

谁帮我？谢谢

airone@airone:/usr/lib/mono/4.5$ ls -l | grep msco
-rw-r--r-- 1 root root 1525760 dic 13 01:46 mscorlib.dll
airone@airone:/usr/lib/mono/4.5$