I
1. Cristina es menos talentosa que Andrés.
2. Pablo es más rápido que Adrian.
***
...mejor que... > ...better than...
...peor que... > ...worse than...
...mayor que... > ...older than...
...menor que... > ...younger than...
3. Ustedes son todos menores que yo.
II
1. Cristina corre más rápido que Andrés.
2. Mariela estudia más horas que Felipe.
3. Pablo canta mejor que yo.
Explanation:
I
Comparison of adjectives.
1. In order to express that someone possesses less quality than the other, we use menos. This word has one single form (for both genders and both numbers) because it defines the adjective it stands by: menos talentosa. The word que is than in English - less talented than : menos talentosa que.
2. When we want to illustrate someone or something as having more quality, we use más. It precedes the adjective and attributes to it, as well as the noun described by the adjective, more quality. But when comparing one's quality to the quality of the other, we mustn't forget que, meaning than - faster than : más rápido que.
***
There are, however, some adjectives that have an irregular comparison. Those are:
bueno/buena ---> mejormalo/mala ---> peorviejo/vieja ---> mayorjoven ---> menor
These forms change in plural (mejor-es/peor-es/mayor-es/menor-es). Not all of these are necessarily irregular (read under the number 3) but the pair bueno/malo are the common irregular adjectives we know are irregular in English, too.
3. When it comes to age, it would be impolite to call somebody más viejo. This is not incorrect but rather inappropriate. Same goes for más joven. The person we are younger then could feel insulted. That is why in the third sentence we use menor and in plural (ustedes).
II
Other comparisons.
1. In this case we compare the running of both subjects. This implies that we are comparing adverbs (which describe actions/verbs). The process is the same as with adjectives. We use más when the quality of the action is better, and we use menos when the action is worse. These words describe adverb so they should be in front of them: más rápido.
2. This time we are comparing the quantity of something, more precisely, the quantity of hours. And if we are comparing the quantity of something, it means that nouns are in comparison. But the rules remain the same: más is when there is more of something, menos when there is less: más horas.
3. Here again we should compare the quality of an action: to sing. But here again we face an exception: well has an irregular comparison (again just as in English) and we must remember that. We cannot say cantar más bien. The comparative of bien is the same as for bueno: cantar mejor.
