I am aware that adjectives only modify nouns, while adverbs modify everything else (verbs, adjectives and other adverbs). However I'm experiencing some difficulty identifying these two expressions from each other:
My previous good computer cost me $500.
My previously good computer cost me $500.
I'm sorta confused on how to interpret the words previous/previously and thus, can't understand how the two sentences are different.
"My previous good computer [...]" means "the good computer I owned before my current good computer".
"My previously good computer [...]" means "my computer which used to be good but is no longer so".
I hope this helps.
I have added some brackets to show how to group the words:
(My (previous (good computer))) cost me $500.
In the past I owned a good computer, and it cost $500. The adjective "previous" modifies "good computer".
(My ((previously good) computer)) cost me $500.
In an unspecified time (but probably the present), I own or owned a computer which cost $500. In the past it was good, and by inference in the present it is not good. The adverb "previously" modifies the adjective "good".
You will often see adjectival phrases written with hyphens, which makes it much clearer: "well-thought-out". (Note that many guides recommend not hyphenating adjectives ending in -ly as a matter of style, but nonetheless "previously-good" is completely understandable.)
