-다고/-라고 그래(요) => "it's said (so)," “it is called . . ."

This sentence ending is a colloquial expression similar to the indirect speech forms -고 해(요) and -래(요). 

• 부산에 산다고 안 그랬니?
  => Didn't you say you live in Pusan?
• 저 건물 이름이 뭐니?
  => What's the name of that building?
• 독립 기념관이라고 그래.
  => They say it's Independence Hall. 

* -고 그래(요) is not to be confused with 그래(요), which has various meanings depending on the context, as shown in these examples: 

• 요즘 방학이니?
  => Are you vacation now? 
• 그래.
  => Yeah.
• 내일 모임에 나올래요?
  => Will you come to the meeting tomorrow?
• 그래요.
  => Yes, I will.
• 요즘 물건값이 너무 비싸요.
  => The prices are too expensive these days.
• 그래요.
  => You are right./I agree.

N. + 중(에) => "among," "in the midst of . . ."

• 시험 중에 전화가 왔다.
  => During the exam, a telephone rang.
• 텔레비전 방송 중에 아기가 울기 시작했다.
  => During the television show, the baby started crying. 
• 학생들 중에 나타샤가 제일 인기다.
  => Among the students, Natasha is the most popular.

A.V. + 는 중(에) => "in the middle/midst of doing . . ."

• 시험을 준비하는 중이야.
  => I am in the midst of preparing for an exam.
• 저녁 식사하시는 중에 죄송합니다.
  => I am sorry (to bother you) in the middle
  of your dinner. 
• 열심히 일을 하는 중에 전화가 왔다.
  => While I was working hard, the telephone rang.

N. + 이/가 아니라 => "it is not N. but . . . ," "not N. but . . ."

This expression amends the action, event, or item in the first part of the sentence by the second part.

• 로스앤젤레스가 아니라 시애틀에 도착했어요.
  => He arrived in Seattle, not Los Angeles.
• 윌키 선생님이 아니라 메뜌가 통역을 했어요.
  => Not Mr. Wilkey, but Matthew interpreted (it). 

V. + ㄴ/은/는 + 것이 아니라 => "it is not (the fact) that," "not . . . but . . ."

This expression amends the action, event, or item in the first part of the sentence by the second part.

• 고속 버스를 타는 것이 아니라 기차를 탈 거예요.
  => We are not taking an express bus, but we will take a train.
• 여기는 날씨만 좋은 게 아니라 사람들도 친절해요.
  => Not only is the weather nice here, but the people are also nice.

Polite suggestions - (으)면 어때요? => "How about . . ."

Politeness is an important aspect of the Korean language. The following list indicates the increasing degrees of politeness.

• -(으)면 어때?
  => "How about it?" (nonpolite) 
• -(으)면 어때요? 
  => "How about it, please?" (polite but informal) 
• -(으)면 어떨까요? 
  => "Would it be all right to . . . ?" (more polite) 
• -(으)면 어떻겠습니까? 
  => "Would you mind if . . . ?" (polite and formal) 
• -(으)면 어떠시겠습니까? 
  => "Would you mind if . . . ?" (polite, formal, and honorific)
• 왕복표를 사면 어때(요)? 
  => How about buying a round-trip ticket? 
• 10 시까지 기다리면 어떨까요? 
  => Would you mind waiting until ten o'clock? 
• 대전에서 주무시면 어떠시겠습니까? 
  => Would you mind staying over in Taejn? 

A.V. + ㄴ/은 지(가) . . . 되다 => "it's been . . . since . . ."

This pattern is used to indicate that a time period has lapsed since the action or event.

• 한국에 온 지(가) 10 년 됐어요.
  => It's been ten years since I came to Korea. 
• 밥 먹은 지(가) 3 시간 됐어요.
  => It's been three hours since I had my meal. 
• 친구를 만난 지 오래 됐어요.
  => It's been awhile since I saw my friend. 
• 고속도로가 생긴 지 얼마나 됐어요?
  => How long has it been since the highway was built?