google了一下:
http://www.sciencenews.org/pages/sn_arc97/10_4_97/bob1.htm
When it comes to milk production, nothing beats Holsteins. For the farmer who takes care to keep them cool, sated with high-energy chow, and milked regularly—often under the management of a sophisticated computer—these familiar black-and-white cows produce an average of 2,275 gallons of milk each per year. The average Brown Swiss, in contrast, produced only 1,820 gallons last year, and a Jersey less than 1,600.
人家也没用将来时啊?still confused,但可以排除A
剩下的只能选e了 |