Used before nouns and noun phrases that denote a single but unspecified person or thing.
예문
1. in a word (한마디로) 2. Rome was not built in a day. (로마는 하루아침에 이루어지지 않았다) 3. A patient came to see me. (환자가 나를 만나러 왔다) 4. take a rest (쉬다) 5. for a week (1주간)
