1. In November 1972, through trial and error, they successfully discovered qinghaosu—the most effective part of the qinghao extract. 📌 名师点睛:教材标准母句,考点典型,适合写作与语法学习。 📖 译林必修第三册 📄 第 45 页 🏷️ 栏目: UNIT4