Explain the distinction between who and whom.

The distinction between "who" and "whom" lies in their usage as pronouns in a sentence. "Who" is used as a subject pronoun, while "whom" is used as an object pronoun.

"Who" is used when referring to the subject of a sentence or clause. For example, in the sentence "Who is going to the party?", "who" is used to ask about the subject of the sentence, the person who is going to the party.

On the other hand, "whom" is used when referring to the object of a verb or preposition. For example, in the sentence "To whom did you give the book?", "whom" is used to ask about the person who received the book, which is the object of the verb "give".

To determine whether to use "who" or "whom," you can try rephrasing the sentence and see if "he" or "him" sounds more appropriate. If "he" sounds better, then "who" is the correct choice. If "him" sounds better, then "whom" is the correct choice.

It is important to note that in informal speech and writing, the use of "whom" is becoming less common, and "who" is often used in its place. However, in formal writing or when following strict grammar rules, it is still important to use "whom" correctly.