graded soil mixture

例句：

1. 1. The engineer graded thesoil mixture for the construction project.
   工程师为建设项目对土壤混合物进行了分级。
2. 2. The farmersmixed different grades of soil to improvethe fertility of their crops.
   农民们混合不同级别的土壤以提高作物的肥力。
3. 3. The construction company used a graded soil mixture to build the foundation ofthe new building.
   建筑公司使用分级土壤混合物来建造新建筑物的基础。