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.
OG46. 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
Choice E, the best answer, uses the adverbial phrase more quickly than to modify the verb phrase gain weight. In A, B, and C, quicker than is incorrect because an adjective should not be used to modify a verb phrase. E is also the only choice with consistent verb tenses. The first verb in the clauses introduced by showed that is exercise. A and B incorrectly compound that present tense verb with a past tense verb, associated. C and D correctly use associate, but C follows with the past tense required and D with the present perfect have required. Both C and D incorrectly conclude with the future tense will gain.
that would also be correct; the split between "...than..." and "...than do...", in this problem, is just meant to be an annoying distraction -- both versions are ok.
you would *need* the "do" if either of the following were true:
1) the verb in the other half of the comparison were written in a different tense;
2) the sentence would be ambiguous without it.
since neither of these is true, both versions are fine.