The grammatically correct phrasing is "How old is she?"
Understanding the Correct Usage
When asking about age, "How old is she?" is the universally accepted and grammatically sound construction in English. The alternative, "How old are she?", is incorrect. This common point of confusion revolves around proper subject-verb agreement, specifically with linking verbs.
The Role of Linking Verbs
The verb "to be" (in forms like is, are, am, was, were) often functions as a linking verb. A linking verb connects the subject of a sentence to information about that subject (like a description or identity).
In the question "How old is she?", "is" serves as the linking verb, connecting the subject "she" to the adjective "old."
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Subject-Verb Agreement: In English grammar, a verb must always agree in number with its subject.
- "She" is a singular pronoun (referring to one person).
- Therefore, it requires a singular form of the verb "to be." The singular third-person form is "is."
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Why "Are" is Incorrect: The verb "are" is used for plural subjects (e.g., "they," "we") or for the second-person singular/plural pronoun "you" (e.g., "How old are you?"). Since "she" is singular, "are" is not the correct choice.
As per grammatical rules, linking verbs like am, is, was, are, were are correctly placed before pronouns such as he, she, it, I, they, and we when forming questions.
Illustrative Examples
To clarify the correct application of linking verbs with different pronouns, consider the following:
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Correct Questions:
- How old is he?
- How old is it? (e.g., referring to a pet or a building)
- How old am I?
- How old are we?
- How old are they?
- How old are you?
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Incorrect Questions (Common Errors):
- How old are he? (Incorrect: "he" is singular)
- How old is them? (Incorrect: "them" is an object pronoun, and plural; should be "How old are they?")
Grammar Guide: Subject-Verb Agreement for "To Be"
The table below summarizes the correct agreement between common subject pronouns and the present tense forms of the linking verb "to be" in questions about age:
| Subject Pronoun | Correct Linking Verb (Present Tense) | Example Question |
|---|---|---|
| I | am | How old am I? |
| You | are | How old are you? |
| He | is | How old is he? |
| She | is | How old is she? |
| It | is | How old is it? |
| We | are | How old are we? |
| They | are | How old are they? |
Mastering subject-verb agreement is a fundamental aspect of clear and correct communication in English.
Further Reading on Grammar
For a deeper dive into subject-verb agreement and other essential English grammar rules, you can explore resources from reputable academic institutions:
