名词中文翻译
中文翻译：次级地层
同义词：
['subsurface', 'lower stratum例句：1. The subgrade is being excavated to prepare for the new road.（正在挖掘次级地层以准备新的道路。）2. The geologists were studying the subgrade of the old city.（地质学家正在研究旧城市的次级地层。）']
例句：
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1. The subgrade is being excavated to prepare for the new road.
正在挖掘次级地层以准备新的道路。
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2. The geologists were studying the subgrade of the old city.
地质学家正在研究旧城市的次级地层。
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3.The subgrade was found to be weak and prone to collapse.
发现次级地层很弱且容易坍塌。