因此,很多学生课间也坐在教室里用功,但学习效率和成绩并不理想用英语翻译

therefore many students sitting in a classroom at the recess time ,study hard , but the learning efficiency and performance is not satisfactory 因此：therefore坐在教室：sitting in a classroom（应该是表示一种状态）课间：at the recess time（这个词组有中场休息的意思）；a break（这个应该比较常用.）效率：efficiencyperformance:表现,在这里指的就是成绩.当然你也可以achievements,score,an academic record等等.不理想：not satisfactory（不让人满意）