sc中比较的问题

mrj1104

32.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
the key:E
NN 帮我解释下是什么在比较，谢谢啦

12604698

里面那个句子的主语they和后面those比较。
正常来讲主谓宾 形式的主语比较，后面需要补出助动词。但是如果后面是those，that，比较特殊。没有明显歧义，无需助动词。