The demonstrators were protesting laws that required them to carry pass books at all times or risk arrest.

VOA: standard.2010.03.21

I think the reason books are bigger and bigger but still carry the same information is that examples are more and more interesting.

我认为书越来越厚但是,所包含的信息仍然不变,原因就在于仅是例子越来越吸引人

耶鲁公开课 - 基础物理课程节选