level of a structure element

例句：

1. 1. The level of the ocean is changing due to climate change.
   由于气候变化，海洋的水平正在发生变化。
2. 2. The students are at different levels in their understanding of the material.
   学生们对材料的理解程度各不相同。
3. 3. The company has set a new level for customer service excellence.
   该公司设定了客户服务卓越性的新标准。