Ошибка обновления Ubuntu и предупреждения [закрыто]

Я попробовал команду sudo apt-get update в своем терминале, но она показала следующее сообщение:

Ign:1 http://archive.ubuntu.com/ubuntu cosmic InRelease
Ign:2 http://archive.ubuntu.com/ubuntu cosmic-updates InRelease
Ign:3 http://archive.ubuntu.com/ubuntu cosmic-backports InRelease
Ign:4 http://archive.ubuntu.com/ubuntu cosmic-security InRelease
Err:5 http://archive.ubuntu.com/ubuntu cosmic Release
  404  Not Found [IP: 91.189.88.174 80]
Err:6 http://archive.ubuntu.com/ubuntu cosmic-updates Release
  404  Not Found [IP: 91.189.88.174 80]
Err:7 http://archive.ubuntu.com/ubuntu cosmic-backports Release
  404  Not Found [IP: 91.189.88.174 80]
Err:8 http://archive.ubuntu.com/ubuntu cosmic-security Release
  404  Not Found [IP: 91.189.88.174 80]
Reading package lists... Done
E: The repository 'http://archive.ubuntu.com/ubuntu cosmic Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu cosmic-updates Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu cosmic-backports Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu cosmic-security Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

Я использую версию 18.10 Ubuntu, и я искал репозитории, но это не помогло. Я прикрепляю свой sources.list ниже:

# deb cdrom:[Ubuntu 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.3)]/ co$
deb-src http://archive.ubuntu.com/ubuntu cosmic main restricted #Added by softw$

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu cosmic main restricted
deb-src http://archive.ubuntu.com/ubuntu cosmic multiverse universe

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu cosmic-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu cosmic-updates restricted main multive$

## 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://archive.ubuntu.com/ubuntu cosmic universe
# deb-src http://us.archive.ubuntu.com/ubuntu/ cosmic universe
deb http://archive.ubuntu.com/ubuntu cosmic-updates universe
# deb-src http://us.archive.ubuntu.com/ubuntu/ cosmic-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://archive.ubuntu.com/ubuntu cosmic multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ cosmic multiverse
deb http://archive.ubuntu.com/ubuntu cosmic-updates multiverse
# deb-src http://us.archive.ubuntu.com/ubuntu/ cosmic-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://archive.ubuntu.com/ubuntu cosmic-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu cosmic-backports main restricted universe 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 cosmic partner
# deb-src http://archive.canonical.com/ubuntu cosmic partner

deb http://archive.ubuntu.com/ubuntu cosmic-security main restricted
deb-src http://archive.ubuntu.com/ubuntu cosmic-security restricted main multiv$
deb http://archive.ubuntu.com/ubuntu cosmic-security universe
# deb-src http://security.ubuntu.com/ubuntu cosmic-security universe
deb http://archive.ubuntu.com/ubuntu cosmic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu cosmic-security multiverse

# This system was installed using small removable media
# (e.g. netinst, live or single CD). The matching "deb cdrom"
# entries were disabled at the end of the installation process.
# For information about how to configure apt package sources,
# see the sources.list(5) manual.

Как я могу это исправить?