ADVERBS
25. Adverbs are derived from adjectives by adding -ment to the féminine form of the adjective, e.g.:
certain fem.: certaine
adverb : certainement; (certainly) régulier fem.: régulière
adverb : régulièrement; (regularly) Adjectives whose last letter is a vowel remain masculine before the adverbial ending -ment, e.g. :
rapide adv.: rapidement (rapidly); infini "* infiniment (infinitely).
26. Adverbs usually follow the verb, and in compound tenses they usually follow the auxiliary:
Louis écrit bien (Louis writes well) ; Louis a bien dormi (Louis rested well)