11. One of four babies are now born to mothers aged thirty years or more, compared with just one of six born in 1975.

(A) of four babies are now born to mothers aged thirty years or more, compared with just one of six born

(B) of four babies is now born to a mother whose age is thirty or older, compared to just one of six babies who were born

(C) baby in four are now born to mothers aged thirty or older, compared to just one in six

(D) baby in four is now born to a mother aged thirty or older, compared with just one in six

(E) baby in four is now born to mothers aged thirty years or more, compared to just one in six

正确为D。 做题时根据谓语单复数和compare with/to的区别可以选出D。 但是有点迷惑的是选项D的compared with just one in six 与one in four 的比较。后面是省略了one in six (is born to mothers aged thirty years or more) in 1975? 选项A中的 one of six born in 1975 与前面的比较对等吗？

后面是省略了one in six (is born to mothers aged thirty years or more) in 1975?

Yes, that's correct.

是省略，但是后面做成从句才好。