Used before nouns and noun phrases that denote a single but unspecified person or thing.
예문
1. Rome was not built in a day. (로마는 하루아침에 이루어지지 않았다) 2. A heavy rain began to fall. (폭우가 내리기 시작했다) 3. A friend of mine in the United States called me yesterday. (미국에 있는 내 친구 하나가 어제 내게 전화를 했다) 4. A dog is faithful. (개는 충직하다) 5. A Mrs. Johnson has come to see you. (존슨 부인이라는 분이 당신을 찾아왔습니다)
