안녕하세요 orbiter님,
제가 좀 설명을 해 드릴께요...
1. -ㅂ/습니다 is called 'formal declarative sentence ending'.
2. the usage of the ending - this ending makes a
formal declarative sentence in the present tense when attached to a verb stem.
basically, this ending makes the whole sentence 'formal'.
For example,
팀이 일합니다. "Tim works (formal)" (일하다 becomes 일하+ㅂ니다 = 일합니다)
팀이 먹습니다. "Tim eats (formal)" (먹다 becomes 먹+습니다 = 먹습니다)
Okay, how about -더라?
Yes, 더라 is one of sentence endings but!!!, it is NOT a 'formal' ending.
-더라 is often used or spoken between friends.
For example,
팀이 일하더라. "Tim works (informal or casual)" (일하다 becomes 일하+더라 = 일하더라)
팀이 먹더라. "Tim eats (informal or casual)" (먹다 becomes 먹+더라 = 먹더라)
remember this - you SHOULD NOT use this 더라 ending when talking to the elder (never!!!).
you should ONLY use this 더라 ending when talking to close friends or the younger.
I hope this helps,
cheers,
Tim