大家帮忙解释一下 GWD 17, Q 24

flomissy

请大家帮忙看一下这题，我选的是 D， 答案是 C。 谢谢！

24.GWD26-Q24

Accordingto United Statescensus data, while there was about one-third of mothers with young childrenworking outside the home in 1975, in 2000, almost two-thirds of those motherswere employed outside the home.

A.     while there was aboutone-third of mothers with young children working outside the home in 1975, in2000, almost two-thirds of those mothers were employed outside the home.

B.     there were aboutone-third of mothers with young children who worked outside the home in 1975;in 2000, almost two-thirds of those mothers were employed outside the home

C.     in 1975about one-third of mothers with young children worked outside the home; in2000, almost two-thirds of such mothers were employed outside the home

D.     eventhough in 1975 there were about one-third of mothers with young children whoworked outside the home, almost two-thirds of such mothers were employedoutside the home in 2000

E.     with about one-thirdof mothers with young children working outside the home in 1975, almosttwo-thirds of such mothers were employed outside the home in 2000

wudiyeah

年份位置要对称，there be 表示自然存在的事物。