我刚刚安装了 ubuntu 12.04。现在，我想安装 g++。所以，我运行命令：
sudo apt-get install g++
但我收到错误：
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
g++-4.6 libstdc++6-4.6-dev
Suggested packages:
g++-multilib g++-4.6-multilib gcc-4.6-doc libstdc++6-4.6-dbg libstdc++6-4.6-doc
The following NEW packages will be installed:
g++ g++-4.6 libstdc++6-4.6-dev
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 6,745 kB/8,389 kB of archives.
After this operation, 24.0 MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Err http://us.archive.ubuntu.com/ubuntu/ precise/main g++-4.6 i386 4.6.3-1ubuntu5
Could not connect to 113.171.224.178:80 (113.171.224.178). - connect (111: Connection refused) [IP: 91.189.91.15 80]
Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/g/gcc-4.6/g++-4.6_4.6.3-1ubuntu5_i386.deb Could not connect to 113.171.224.178:80 (113.171.224.178). - connect (111: Connection refused) [IP: 91.189.91.15 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
接下来，我运行命令：
sudo apt-get 更新
我也收到其他人
Hit http://us.archive.ubuntu.com precise Release.gpg
Get:1 http://security.ubuntu.com precise-security Release.gpg [198 B]
Hit http://extras.ubuntu.com precise Release.gpg
Hit http://ppa.launchpad.net precise Release.gpg
Get:2 http://us.archive.ubuntu.com precise-updates Release.gpg [198 B]
Get:3 http://us.archive.ubuntu.com precise-backports Release.gpg [198 B]
Get:4 http://security.ubuntu.com precise-security Release [49.6 kB]
Hit http://extras.ubuntu.com precise Release
Hit http://us.archive.ubuntu.com precise Release
Hit http://ppa.launchpad.net precise Release
Get:5 http://us.archive.ubuntu.com precise-updates Release [49.6 kB]
Hit http://extras.ubuntu.com precise/main Sources
Hit http://ppa.launchpad.net precise/main Sources
Get:6 http://security.ubuntu.com precise-security/main Sources [65.1 kB]
Hit http://extras.ubuntu.com precise/main i386 Packages
Hit http://ppa.launchpad.net precise/main i386 Packages
Get:7 http://us.archive.ubuntu.com precise-backports Release [49.6 kB]
Ign http://extras.ubuntu.com precise/main TranslationIndex
Ign http://ppa.launchpad.net precise/main TranslationIndex
Get:8 http://security.ubuntu.com precise-security/restricted Sources [1,950 B]
Get:9 http://security.ubuntu.com precise-security/universe Sources [24.0 kB]
Get:10 http://security.ubuntu.com precise-security/multiverse Sources [1,380 B]
Get:11 http://security.ubuntu.com precise-security/main i386 Packages [245 kB]
Get:12 http://us.archive.ubuntu.com precise/restricted Sources [5,470 B]
Hit http://us.archive.ubuntu.com precise/universe Sources
Hit http://us.archive.ubuntu.com precise/multiverse Sources
Hit http://us.archive.ubuntu.com precise/main i386 Packages
Hit http://us.archive.ubuntu.com precise/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise/universe i386 Packages
Hit http://us.archive.ubuntu.com precise/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise/main TranslationIndex
Get:13 http://us.archive.ubuntu.com precise-backports Release [49.6 kB]
Get:14 http://us.archive.ubuntu.com precise/main Sources [934 kB]
Ign http://us.archive.ubuntu.com precise-backports Release
Get:15 http://security.ubuntu.com precise-security/restricted i386 Packages [3,968 B]
Get:16 http://security.ubuntu.com precise-security/universe i386 Packages [73.0 kB]
Get:17 http://security.ubuntu.com precise-security/multiverse i386 Packages [2,369 B]
Hit http://security.ubuntu.com precise-security/main TranslationIndex
Hit http://security.ubuntu.com precise-security/multiverse TranslationIndex
Hit http://security.ubuntu.com precise-security/restricted TranslationIndex
Hit http://security.ubuntu.com precise-security/universe TranslationIndex
Hit http://security.ubuntu.com precise-security/main Translation-en
Hit http://security.ubuntu.com precise-security/multiverse Translation-en
Hit http://security.ubuntu.com precise-security/restricted Translation-en
Hit http://security.ubuntu.com precise-security/universe Translation-en
Ign http://extras.ubuntu.com precise/main Translation-en_US
Ign http://ppa.launchpad.net precise/main Translation-en_US
Ign http://extras.ubuntu.com precise/main Translation-en
Ign http://ppa.launchpad.net precise/main Translation-en
Hit http://us.archive.ubuntu.com precise/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise/universe TranslationIndex
Get:18 http://us.archive.ubuntu.com precise-updates/main Sources [374 kB]
Get:19 http://us.archive.ubuntu.com precise-updates/restricted Sources [5,494 B]
Get:20 http://us.archive.ubuntu.com precise-updates/universe Sources [83.4 kB]
Get:21 http://us.archive.ubuntu.com precise-updates/multiverse Sources [4,746 B]
Get:22 http://us.archive.ubuntu.com precise-updates/main i386 Packages [603 kB]
Get:23 http://us.archive.ubuntu.com precise-updates/restricted i386 Packages [10.1 kB]
Get:24 http://us.archive.ubuntu.com precise-updates/universe i386 Packages [194 kB]
Get:25 http://us.archive.ubuntu.com precise-updates/multiverse i386 Packages [10.4 kB]
Hit http://us.archive.ubuntu.com precise-updates/main TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise/main Translation-en
Ign http://us.archive.ubuntu.com precise-backports/main Sources/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/restricted Sources/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/universe Sources/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/multiverse Sources/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/main i386 Packages/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/restricted i386 Packages/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/universe i386 Packages/DiffIndex
Ign http://us.archive.ubuntu.com precise-backports/multiverse i386 Packages/DiffIndex
Hit http://us.archive.ubuntu.com precise-backports/main TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise/restricted Translation-en
Hit http://us.archive.ubuntu.com precise/universe Translation-en
Hit http://us.archive.ubuntu.com precise-updates/main Translation-en
Hit http://us.archive.ubuntu.com precise-updates/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-updates/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-updates/universe Translation-en
Hit http://us.archive.ubuntu.com precise-backports/main Sources
Get:26 http://us.archive.ubuntu.com precise-backports/restricted TranslationIndex [3,341 kB]
Hit http://us.archive.ubuntu.com precise-backports/restricted Sources
Hit http://us.archive.ubuntu.com precise-backports/universe Sources
Hit http://us.archive.ubuntu.com precise-backports/multiverse Sources
Hit http://us.archive.ubuntu.com precise-backports/main i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/universe i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/main Translation-en
Hit http://us.archive.ubuntu.com precise-backports/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-backports/universe Translation-en
Fetched 7,012 kB in 19s (352 kB/s)
W: GPG error: http://us.archive.ubuntu.com precise-backports Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/precise-backports/restricted/i18n/Index No Hash entry in Release file /var/lib/apt/lists/partial/us.archive.ubuntu.com_ubuntu_dists_precise-backports_restricted_i18n_Index
E: Some index files failed to download. They have been ignored, or old ones used instead.
要检查存储库，我运行命令：cat /etc/apt/sources.list。下面是输出
# deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release i386 (20130213)]/ precise main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ precise main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise universe
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise multiverse
deb http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu precise-security main restricted
deb-src http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://security.ubuntu.com/ubuntu precise-security universe
deb-src http://security.ubuntu.com/ubuntu precise-security universe
deb http://security.ubuntu.com/ubuntu precise-security multiverse
deb-src http://security.ubuntu.com/ubuntu precise-security multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu precise partner
# deb-src http://archive.canonical.com/ubuntu precise partner
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main
请帮我在 Ubuntu 上安装 g++。gcc的版本是4.6.3
非常感谢