我正在尝试基于自定义简单php框架安装一些项目。当我尝试运行项目时，出现错误：Uncaught RuntimeException：使用基于intl的筛选器需要本机PHP intl扩展（http://php.net/manual/en/book.intl.php）。
我正在使用ubuntu 7.10和php7.1。因此，我尝试使用“ sudo apt-get install php7.1-intl”进行安装，并得到了这个提示：
Reading package lists... Done
Building dependency tree
Reading state information... Done
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:
php7.1-intl : Depends: php7.1-common (= 7.1.17-0ubuntu0.17.10.1) but 7.1.19-1+ubuntu17.10.1+deb.sury.org+1 is to be installed
E: Unable to correct problems, you have held broken packages.
我已经尝试过了：
1）sudo add-apt-repository ppa：ondrej / php
2）sudo apt-get更新
3）sudo apt-get install php7.1-intl
遇到相同的错误！