Testing yourself with information on cards is a useful device for studying.用卡片上的信息做自我测试是一种有效的学习方法。He struggled to find time for studying after work.他下班后努力挤时间学习。Microscopy is an invaluable technique for studying the structure of cells.显微镜学是细胞结构研究的一项宝贵的技术。