GWD-12-Q30看了讨论帖还是不懂

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.

1. than

2. than born

3. than they were

4. than there had been
5. than had been born

选了B

答案是A

做题的时候把话是补充完全了的，more babies were born to women over the age of 30 than (babies were born to woemn) under it.

省略要遵循什么规则？

看了cwang的比较之庖丁解牛，那这句要怎样运用规则呢？

谢谢~~~~~~~~~~~~~~~~~~

你自己都已经把省略的补出来了,怎么还不明白呢?

要就不省,要就全省

为什么别的单词省了而把born留着呢?它很牛吗?