zone leveled single crystal

例句：

1. 1. The city is divided into several zones for convenience.
   为了方便，这个城市被分成了几个区域。
2. 2. The scientists are working on a project that spans across multiple zones.
   科学家们正在研究一个跨越多个区域的项目。
3. 3. The government has announced plans to expand the economic zone.
   政府宣布了扩大经济区的计划。