the circulation of weekly magazines exceeded that of newspapers in that period为什么是that of,
问题描述：
the circulation of weekly magazines exceeded that of newspapers in that period为什么是that of,
这个of
答
that 用来指代上文的 the circulation,完整的是the circulation of weekly magazines exceeded the circulation of newspapers in that period.为了避免重复,the circulation 用that 来代替.