cover strata

例句：

1. 1. The geologist is analyzing the layers of rock to determine the age of the earth.
   地质学家正在分析岩石的层次来确定地球的年龄。
2. 2. The study of stratigraphy is crucial for understanding the history of our planet.
   地层学的研究对于我们理解地球的历史至关重要。
3. 3. The construction crew carefully covered the strata with a layer of sand before starting work.
   施工队在开始工作之前，小心翼翼地用一层沙土覆盖了地层。