Breakdown of gapjagi joheun saenggagi deureosseoyo.
Questions & Answers about gapjagi joheun saenggagi deureosseoyo.
갑자기 means suddenly or all of a sudden.
It is an adverb, so it describes how the idea came to mind. Putting it at the beginning is very natural in Korean, because it sets the scene for the whole sentence:
갑자기 + 좋은 생각이 들었어요
= Suddenly, a good idea occurred to me.
You can sometimes move adverbs around in Korean, but sentence-initial 갑자기 is one of the most common and natural placements.
In Korean, words like 좋다 work like descriptive verbs, and when they directly describe a noun, they must change into a noun-modifying form.
So:
- 좋다 = to be good
- 좋은 = good, when placed before a noun
That gives:
- 좋은 생각 = a good idea / a good thought
So 좋은 is the correct form because it is modifying 생각.