week 1 字源

prefix：A prefix is an affix which is placed before the stem of a word. Adding it to the beginning of                one word changes it into another word.
suffix：A suffix is an affix which can alter the form placed after the stem of a word

diversity        <=>  universe
di-:seperate            uni-:together


de-:down、away from
ex:decline

-tive can form a noun or an adjective


Psycology is relate with the story of Psyche and Eeros.
Psyche then turn as the symbol of spirits