Our friend was a sailor and nature enthusiast, and he pointed out that all of the rock cliffs along the lakeshore had right-angle fractures.He wanted to know why.

• 而教师们也在自然地阐述知识和学问的过程中，在理智地介绍自己学术思想及成果的过程中，完成对学生的教育和培养任务。