Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).

Both options listed by the original poster sound natural to my (American) ear. Which one is more natural to me than “who”? If a man did not accept what they were ten

years ago, he must have died.

I would avoid “who”. I try to avoid making decisions between “who” and “whom”. How will I distinguish between who and whom interrupt my thoughts, both when speaking a sentence (or writing) and when reading a sentence (see fig. 2.8)?

In other words, the choice between “who” and “whom” is consciously learned, not natural (in American English).