Making the superlative form for adverbs is even more difficult than the comparative form. Many Americans avoid doing it, so you might not hear it used very often.

He rides his bike most frequently in the morning.

I work at school and at home during the week, but I work most comfortably at my desk on the weekend.

She is most likely to become a doctor after she finishes med school.

Birds sing most beautifully in the morning.

Some adverbs don't use "ly" endings. For these words, just add "est."

• They play well together, but they play best when they're under pressure.

• They perform the worst on the field when they don't practice.

• John is the hardest working player on the team.

• Burt runs the fastest, so he's a wide receiver.