OG46为什么违反if条件从句的时态规律？

46. A study commissioned by the Department of Agricul­ture showed that if calves exercise and associated with other calves, they will require less medication and gain weight quicker than do those raised in confinement.

(A)  associated with other calves, they will require less medication and gain weight quicker than do

(B)  associated with other calves, they require less medication and gain weight quicker than

(C)  associate with other calves, they required less
                medication and will gain weight quicker than do

(D)  associate with other calves, they have required less
                medication and will gain weight more quickly
                than do

(E)   associate with other calves, they require less
                medication and gain weight more quickly than

答案选e没问题。但是if条件从句用一般现在时，主句应该用将来时。为什么这里不是这样用？

OG解释最后一句竟然是Both C and D incorrectly conclude with the future tense will gain.请牛牛们解释一下。

我也同意楼上的说法

因为前面是过去时,理论上后面从句if也应该是过去时,但是却不是,可能就是在暗示是自然现象

纯粹是"砖",用以"引玉"