geology steel tube

例句：

1. 1. Geologists study the earth's crust and mantle to understand itsstructure and history.
   地质学家研究地球的地壳和地幔，以了解其结构和历史。
2. 2. Thegeologist discovered a newspecies of fossil in the cave.
   这位地质学家在洞穴里发现了一种新的化石物种。
3. 3. Geology is an importantfield for studying the Earth's pastand present.
   地质学是研究地球过去和现在的重要领域。