Ubuntu 安装gcc-4.8的问题

[徐九五]

本人linux菜鸟一只，由于在学习C++11，想安装一下gcc-4.8，Ubuntu版本是12.04，在安装的ppa的过程中

sudo add-apt-repository ppa:ubuntu-toolchain-r/test

老是出现一下错误
Traceback (most recent call last):
File "/usr/bin/add-apt-repository", line 128, in <module>
ppa_info = get_ppa_info_from_lp(user, ppa_name)
File "/usr/lib/python2.7/dist-packages/softwareproperties/ppa.py", line 84, in get_ppa_info_from_lp
curl.perform()
pycurl.error: (7, "couldn't connect to host")
求大神解决，谢谢。