plus ... que = more ... than
moins ... que = less ... than
aussi ... que = as ... as

La fourmi est plus rapide que l'escargot.	The ant is faster than the snail.
Elle est moins difficile que sa copine.	She is less difficult than her friend.
Le garçon est aussi grand que sa soeur.	He is as tall as his sister.

bon --- meilleur
mauvais --- pire
bien --- mieux
mal --- pis (plus mal)

Elle est meilleure en français qu'en histoire.	She is better in french than in maths.
Mon gateau est pire que le tien.	My cake is worse than yours.
Sophie chante mieux que Lucie.	Sophie sings better than Lucie.
Il joue plus mal/pis que Paul.	He plays worse than Paul.