我正在尝试使用 更新我的系统apt-get，但它给了我这个错误
Err http://bd.archive.ubuntu.com raring Release.gpg
Could not connect to bd.archive.ubuntu.com:80 (116.193.170.18), connection timed out
Err http://bd.archive.ubuntu.com raring-updates Release.gpg
Unable to connect to bd.archive.ubuntu.com:http:
Err http://bd.archive.ubuntu.com raring-backports Release.gpg
Unable to connect to bd.archive.ubuntu.com:http:
Reading package lists... Done
W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring/Release.gpg Could not connect to bd.archive.ubuntu.com:80 (116.193.170.18), connection timed out
W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring-updates/Release.gpg Unable to connect to bd.archive.ubuntu.com:http:
W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring-backports/Release.gpg Unable to connect to bd.archive.ubuntu.com:http:
W: Some index files failed to download. …