求翻译：16单元是第二册的第二个单元，也就是说是这个新学期的第二单元。16单元的主题是围绕“问路和指路”展开的，同时教学生，如何用情态动词“Can”和“May”来表达许可和可能。在第二册上学期的课本中，学生已经学到了一些关于“问路和指路”的知识，而且他们也知道一部分关于许可的表达，比如“May I come in？”“Can I borrow your pen？”“May I speak to Ann，please？”等等。是什么意思？

16 unit is the second book of the second unit, that is is the second unit of the new term. 16 unit is built around the subject of "asking the way and the way", while teaching students how modal verb "Can" and "May" to express license and likely. On the second term textbooks, students have learned something about "asking the way and the way" of knowledge, and they know the part about license expression, such as "May I come in? ”“Can I borrow your pen？ ”“May I speak to Ann，please？ "And so on.