ubuntu - virtualbox网络问题

Question

在virtualbox中安装了虚拟机ubuntu，网络配置中只有一个网卡，其他的是灰色，这是为什么啊，怎么配置，ubuntu，才能使得网卡2可以用呢？在/etc/network/interface 添加一个eth1，启动是老师报：Cannot find device "eth1"。在debian中怎么就没事呢

但是另一个虚拟机debian却有两个：

Answer 1

After my own experiment just now, I think you can set it up by turning off the running Ubuntu virtual machine first.

Answer 2

Correct answer upstairs, the configuration of the virtual machine cannot be modified while it is running.