问题
选择题
The school year is divided into two semesters, __________is September through December.
A．the first of which
B．the first of them
C．the first of it
D．the first of that
答案
答案：A
考查定语从句。__________is September through December.是非限制性定语从句，先行词是semesters，them和it 不能引导定语从句，that不能引导非限制性定语从句，所以选A。