Elderly patients, many who take expensive brand-name

[ArjunJ720]

Hi,

Upon reviewing my CAT exams , I came across this sentence correction question that I got wrong.

Elderly patients, many who take expensive brand-name medications daily, could reduce their medical costs by switching to generic drugs and making lifestyle changes.

(A) many who
(B) many of them who
(C) and many of them who
(D) many of whom
(E) many of which

The correct answer is (D). I looked up when to use who vs. whom and found out that who should refer to the subject and whom should refer to the object. My question is, how do I know that patients is the object by reading this sentence?

Thanks.

[Chelsey Cooley]

Nice question. The safest way to determine whether to use "who" or "whom" is to decide whether it makes more sense to replace "who/m" with "they" or with "them". The biggest clue in this sentence is the word "many": even though you might say "they take expensive medications daily," you'd never say "many they take expensive medications daily." Instead, you'd say "many of them", which points us to "whom."

Even though "elderly patients" is the subject of the first part of the sentence, adding in "many" means that in the second part of the sentence, in order to use correct, idiomatic English, we need to make it the object of the preposition "of." What matters isn't whether the noun is initially the subject or the object; what matters is which role it's playing when it gets replaced by either "who" or "whom".