Choose the right forms of the adverbs to complete the sentences.

Choose the correct option.

Percy drives [carefullier |more carefully|carefulliest |most carefully] after watching an instructional video.

Jim can run [faster |more fast|fastest |most fast] than John.

He worked [harder |more hard|hardest |most hard] in the team.

Birds fly [lower|more low|lowest |most low] than planes.