APT-GET INSTALL问题

tassel

Debian 4.0 R5系统，最近出现了一个奇怪的问题：
apt-get install sudo
Reading package lists... Done
Building dependency tree... Done
You might want to run `apt-get -f install' to correct these:
The following packages have unmet dependencies:
  php-db: Depends: php-pear but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).
我试过－f，也不对，错误跟下面的一样，也是需要php-db，安装了这个还有其它的错误等着，什么问题？有人见过这个问题吗？

tassel