What Clark means is that libraries have shifted from simply being storehouses of books to a medium to help "bridge the gap between the haves and the have-nots".

克拉克的意思是，图书馆已经从简单的书籍存放仓库转变为一种媒介，它能够起到“弥合富人和穷人之间的鸿沟“的作用。

Especially the why nots.

特别是为什么穷国。

They tend to have strong shoulds and should-nots.

他们倾向于有强烈该做和不该做的事。

She'd put these what nots in her hair as decoration.

她在圣诞树上放了一些装饰品。

the “have-nots” are making more trips but buying less.

“贫穷”一族的反而变多了，但是买的少了。