happy <—-> happily
quick <—-> quickly
bad <—-> badly
careful <—-> carefully
Perbedaan adjective dan adverb of manner adalah, adjective menerangkan noun (kata benda) sedangkan adverb of manner menerangkan verb (kata kerja).
Bandingkan :
They always give us a quick response. (quick menerangkan response)
They respond us quickly. (quickly menerangkan respond)
Adjective seperti hard, late, fast dan early tidak berubah ketika menjadi adverb of manner. Memang ada kata hardly dan lately tapi artinya berbeda, hardly artinya hampir tidak dan lately artinya akhir-akhir ini.
 Bandingkan :
He is a hard worker. <—-> He works very hard.
They are fast learners. <—-> They learn fast.
The payment is late now. <—-> They paid late this month.
Early marriage is not good. <—-> They got married early.
Adverb of manner dari ‘good’ bukanlah ‘goodly‘ tetapi ‘well’.
Bandingkan :
He is a good teacher. <—-> He teaches well.
The team is good. <—-> The team plays well.
Kita menggunakan adjective bukan adverb of manner setelah linking verb seperti seem, look, appear, become, sound, taste, feel dan sebagainya.
