According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.
GWD-12-Q30: According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.
A. than B. than born C. than they were D. than there had been E. than had been born 请问这道题为什么选A呢,对于比较题型的比较对象我老是分不清 谢谢各位~~