一、在形容詞詞尾直接加-ly.如:real-really; helpful-helpfully; careful-carefully; hopeful-hopefully; slow-slowly; quick-quickly; quiet-quietly

二、以子音字母加y結尾的形容詞要變y為i,然後再加-ly.如:busy-busily; angry-angrily; easy-easily

三、某些以子音字母加不發音的字母e結尾和以-ue結尾的形容詞要先去掉e,然後再加-y或-ly.如:terrible-terribly; true-truly; gentle-gently

另外,副詞還可以由形容詞加字首a-得來,如:loud (adj.)-aloud (adv.)

此外,部分名詞加字尾也可變成副詞,如:part-partly.

例句:It is partly her fault.有部分是她的錯.

需注意:friendly; motherly; lovely等詞是形容詞而非副詞.