求教一道OG15verbal分册sc，走过路过不要错过

lxr282828

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 原句
B associated with other calves, they require less medication and gain weight quicker than
C associate with other calves, they require less medication and 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


OG中对句中comparison的比较的解释如下：These calves gain weight more quickly than other calves. The comparison is between calves and those(another type of calves); the verb do ungrammatically interrputs the comparison and should be elminated

前半句我理解，的确是calves与其他calves的比较，但我觉得加上do，句子就变成了they require less medication and gain weight more quickly than do those raised in confinent.
They与those形成主语比较也没错，没必要eliminate啊，请NN指点

lxr282828

有人么。。。。。。。。。

lxr282828

秒沉啊，手工顶上去