This is the 291st most frequent Korean word.
이들이
"이들이" means "these people" in English.
이들이 is used here as a subject meaning 'they', referring to a group of people.
이들이 어떻게 문제를 해결할지 지켜봐야 합니다.
We need to observe how they will solve the problem.
이들이 is demonstrating the group who proposed the ideas, emphasizing them as the proposers.
이들이 제안한 아이디어는 매우 혁신적입니다.
The ideas proposed by them are very innovative.
이들이 is highlighting 'they' as the agents who showed courage, focusing on their action and characteristic.