This is the 645th most frequent Korean word.
상당한
Considerable; significant.
Here, '상당한' describes '발전', indicating that the progress achieved is of notable or appreciable significance.
상당한 발전이 이루어졌습니다.
Considerable progress has been made.
Here, '상당한' is used to describe '능력', emphasizing the significant or remarkable nature of his skills or capabilities.
그는 상당한 능력을 가지고 있습니다.
He possesses considerable abilities.
In this sentence, '상당한' modifies '시간', suggesting that a notable amount of time is needed for the project.