To achieve the purpose of storing industry solid wastes and enhancing subgrade stability in seasonally frozen regions, Structure III, which utilized modified silty clay (SC) and extruded polystyrene (XPS) board as a novel subgrade thermal insulation layer (NSTIL), was presented.

这句话是不是要在modified silty clay和extruded polystyrene (XPS) board前加上the？还是只在modified silty clay前加就可以，这是我书写文章的摘要中的第一句话，这个the的使用太难了，还请老师解答!