Question

In the following sentence, should "Who" or "Whom" be used in the blank space?: ___ understands the contents of this document?

Answer 1

Hint: In the given sentence, we have to choose the pronoun that expresses the doer of the action, that is, understanding the documents in this case. It is a type of subjective pronoun.

Complete answer:
A pronoun is a term that replaces a noun or a noun phrase in a sentence. Pronouns refer to either a previously specified noun or a noun that does not need to be named precisely.

The subjective pronoun "who" refers to the person who does the activity. “That's the girl who scored the goal,” for example. Because the female was doing the scoring, it is the topic of "scored." The action is thus given to "whom," the objective pronoun. “Who do you prefer?” for example. It is the “liked” thing.

The answer depends on whether you're talking about the sentence's subject (the noun that's doing the activity) or the sentence's object (the noun that is having an action performed on them).

If someone can comprehend the contents of a document, they are the subject, thus "Who" is the right form.
If you asked, "Whom was this document delivered to?" you might use "Whom."

Thus, for the above question, the correct answer is “Who”

Note: Because it is employed as the subject of a verb, "who" is similar to "he/she." Who enjoys milk in tea? (Compare this with "He enjoys milk in his tea.")
Because it is employed as an object, "whom" is similar to "him/her."
For instance, Nikita saw them on the train? (Compare this to "Nikita" saw him in the train.")