How old is ______?

The question tests the correct usage of possessive adjectives and possessive pronouns in English. The phrase "How old is ______?" is a common way to ask someone's age. Possessive adjectives (my, your, his, her, its, our, their) precede a noun to modify it. Possessive pronouns (mine, yours, his, hers, its, ours, theirs) stand alone and replace a noun or noun phrase. In the sentence "How old is ______?", the blank requires a word that can function as either a subject complement or a possessive pronoun. Let's analyze the options: - **he**: This is a subject pronoun. If it were a subject complement, the sentence structure would be different. However, "How old is he?" is a grammatically correct and common question asking for a male person's age. - **her**: This is a possessive adjective (e.g., "her book") or an object pronoun. "How old is her?" is grammatically incorrect. - **hers**: This is a possessive pronoun. "How old is hers?" could be grammatically correct if it refers to "hers [something]" (e.g., "How old is hers?"), but it's less common for asking a person's age directly. - **his**: This can be a possessive adjective (e.g., "his book") or a possessive pronoun. Similar to "hers", "How old is his?" can be understood to mean "How old is his [something]?" (e.g., "How old is his car?"), but it's less direct than asking about the person themselves. Considering the most common and direct way to ask someone's age, "How old is he?" (asking about a male) or "How old is she?" (asking about a female) are the standard forms. Given the options, "he" is the only one that directly forms a complete and common question about a person's age. Therefore, assuming the question aims for the most idiomatic and grammatically sound completion for asking a person's age, "he" is the correct choice, forming the question "How old is he?".