统一股份：公司三季度毛利率比去年同期微升，主要是由于基础油成本的下降

Group 1 - The core viewpoint of the article is that the company's gross margin in the third quarter has slightly increased compared to the same period last year, primarily due to a decrease in base oil costs [2] Group 2 - The company reported a rise in gross margin, indicating improved profitability [2] - The increase in gross margin is attributed to lower costs of base oil, which is a significant input for the company's operations [2]