[求助]T-4-Q12 各位NN帮我看看吧～～～

T-4-Q12

For the farmer who takes care to keep them cool, providing them with high-energy feed, and milking them regularly, Holstein cows are producing an average of 2,275 gallons of milk each per year.

A.      providing them with high-energy feed, and milking them regularly, Holstein cows are producing

B.       providing them with high-energy feed, and milked regularly, the Holstein cow produces

C.      provided with high-energy feed, and milking them regularly, Holstein cows are producing

D.      provided with high-energy feed, and milked regularly, the Holstein cow produces

E.       provided with high-energy feed, and milked regularly, Holstein cows will produce

正确答案是E

D为什么错？为什么E用will produce呢？这里不是说它每年可以生产这么多的牛奶，不是应该用一般现在时么？