使用了ubuntu在gui下只能用DHCP获取IP，不能手动设置，查了相关资料。终于解决：
gedit /etc/network/interfaces
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 192.168.0.200
netmask 255.255.255.0
gateway 192.168.0.1
#auto wlan0
#iface wlan0 inet dhcp
sudo /etc/init.d/networking restart
照此思路，修改 /etc/network/interfaces ，无线网卡也能用了
把文件中对应无线网卡的部分修改为如下形式
auto eth1
iface eth1 inet static
wireless-rate 54M
wireless-essid TP-LINK
wireless-key AAAAABBBBB
address 192.168.1.140
netmask 255.255.255.0
gateway 192.168.1.1
