a line of demarcation的用法和样例：
- A lorry drove into a line of parked cars.
- Riyue Mountain is a watershed for valley of eastern Qinghai and inland river, it is also a line of demarcation for agriculture and herd industry in eastern Qinghai area.
- The reddening sky threw into relief a line of trees on the horizon.
- A line of palm trees fringe the swimming pool.
- A line of verse consisting of five metrical feet.