Can someone please explain these few spanish 2 topics? * -car, -gar, -zar verbs in the preterite and imperfect tense
* Stem-changing verbs in the imperfect and preterite tense
* Contractions al and del

Which in spanish an example of: 1) a comparison between two unlike things, and 2) something that you consider the best. when creating your two sentences make sure to use the following expressions: mejor que, peor que, el/la mejor, el/la peor