Adverb Irregular Comparisons
There are three degrees of comparison in adverbs:
The one-syllable adverbs use -er in the comparative form, and -est in the superlative form. Adverbs that end in –ly use the words more and most to form their comparatives and superlatives.
It is impossible to have comparatives or superlatives of adverbs denoting time, place, and degree.
When indicating comparison (the highest degree in comparison to other things or people) the is used in front of the superlative adverb.
She sang the most beautifully of all (i.e., in comparison to others).
When we just intensify a superlative adverb identifying its meaning with very we don't use the in front of it.
She sang most beautifully (i.e., very beautifully).