当我尝试关闭运行 ubuntu 16.04.5 的电脑时，它会挂在这条线上：
A stop job is running for Raise network interfaces (1s/1min 31s)
这是我的 /etc/network/interfaces 文件：
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
source /etc/network/interfaces.d/*
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
allow-hotplug enp0s31f6
iface enp0s31f6 inet dhcp
我添加了 allow-hotplug 因为我在启动时遇到另一个错误
A start job is running for Raise network interfaces (1s/5min 2s) …