There are differences between literary language and spoken language. There are a lot of expressions that are widely used in writing, but are rarely used in casual speech. Also more contractions and omissions are used in speech than in (formal) writings. See thiscredit goes to the book "국어실력이 밥 먹여준다":
- 그러나 나는 누나와 함께 이곳에서 가장 큰 것을 찾아 동생에게 가져다 주어야 해.
Chances are, nobody speaks like this in real life. You're more likely to say:
- 하지만 난 누나랑 같이 여기서 제일 큰 걸 찾아서 동생한테 갖다 줘야 돼.
그러나, 이곳, 가장, 에게, -어야 하다, etc are literary expressions that are rarely used in casual speech, and are replaced with 하지만, 여기, 제일, 한테, -어야 되다. Also 나는, 것을, 가져다, 주어야 are contracted to 난, 걸, 갖다, 줘야. Also the -아 connecting ending is replaced with -아서 to make it sound more apparent.