Vídeo com explicação: https://www.youtube.com/watch?v=0HPKwhngB-U
Link1: http://www.grammarbank.com/adjective-or-adverb.html
Link2: http://www.grammarbank.com/adjective-adverb-worksheet.html
Link 3: http://www.english-grammar.at/worksheets/adjective_adverb/ad5.pdf