尝试升级时这些是什么No candidate ver以及出现什么错误？Failed to read mirror file
Ign http://old-releases.ubuntu.com lucid/multiverse Translation-en
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Ign http://old-releases.ubuntu.com lucid/universe Translation-en
Ign http://old-releases.ubuntu.com lucid-security/main Translation-en
Ign http://old-releases.ubuntu.com lucid-security/multiverse Translation-en
Ign http://old-releases.ubuntu.com lucid-security/restricted Translation-en
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Fetched 29.4 kB in 6s (4877 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done
No candidate ver: belocs-locales-bin
No candidate ver: libbind9-30
No candidate ver: libcupsys2
No candidate ver: libdatrie0
No candidate ver: libdns35
No candidate ver: libevent1
No candidate ver: libisc35
No candidate ver: libisccc30
No candidate ver: libisccfg30
No candidate ver: liblwres30
No candidate ver: libxcb-xlib0
No candidate ver: system-services
No candidate ver: upstart-compat-sysv
No candidate ver: upstart-logd
Updating repository information
WARNING: Failed to read mirror file