有时，当我安装东西时，我会收到如下错误：
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed
E: Unable to correct problems, you have held broken packages.
我该如何解决这个问题？
package-management apt ppa dependencies software-installation
apt-get update和 和有apt-get upgrade什么区别？
我应该先运行哪个？
它们中的任何一个会自动运行另一个吗？
我想知道为什么upgrade有时不想升级系统的某些部分，而dist-upgrade确实如此。这是运行后的示例apt-get upgrade：
apt-get upgrade：
rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
linux-generic linux-headers-generic linux-image-generic
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
与apt-get dist-upgrade：
rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following NEW packages will be installed:
linux-headers-3.0.0-13 linux-headers-3.0.0-13-generic
linux-image-3.0.0-13-generic …我使用 Software Sources 程序添加了一些额外的存储库。但是当我重新加载包数据库时，出现如下错误：
W：GPG 错误：http : //ppa.launchpad.net trusty InRelease：以下签名无法验证，因为公钥不可用：NO_PUBKEY 8BAF9A6F
apt-key根据官方的 Ubuntu 文档，我知道我可以在终端中修复它。但我希望以图形方式进行。有没有办法在不使用终端的情况下做到这一点？
当我检查更新时，出现“无法下载存储库信息”错误。
这是详细信息下的内容：
W: Failed to fetch gzip:/var/lib/apt/lists/partial/us.archive.ubuntu.com_ubuntu_dists_natty_main_source_Sources Hash Sum mismatch,
E: Some index files failed to download. They have been ignored, or old ones used instead.
我已经尝试了正常的方法，sudo apt-get install python3.6但是……好吧……那没有用。
那么，我该怎么办呢？（我最好不要自己构建它）
我正在使用 Ubuntu 16.04。
计算机在一个窗口中给了我这个输出：
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.
我怎样才能解决这个问题？
如何通过 将软件包降级到旧版本apt-get？
其他工具也可以接受，但apt-get最好使用。
最近更新后，ttf-mscorefonts-installer提示我接受其许可协议。
??????????????????? Configuring ttf-mscorefonts-installer ???????????????????
? ?
? TrueType core fonts for the Web EULA
?
? END-USER LICENSE AGREEMENT FOR MICROSOFT SOFTWARE
?
? IMPORTANT-READ CAREFULLY: This Microsoft End-User License Agreement
? ("EULA") is a legal agreement between you (either an individual or a
? single entity) and Microsoft Corporation for the Microsoft software
? accompanying this EULA, which includes computer software and may include
? associated media, printed materials, and "on-line" or electronic
? documentation ("SOFTWARE …有没有办法可以查看我在sources.list 中配置的档案中的所有版本。我可以用 看到每个档案的最后一个版本apt-get policy，但我怎样才能看到它们呢？
有什么办法可以包括PPA和sources.list.d 中的任何内容？