Identifying the Subject of a Sentence

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 The Subject (S) of a sentence is the person, thing, or idea that performs the action or about which something is stated. It can often be found by asking "Who?" or "What?" before the verb.

Examples:

1. Amy laughed.

   • Q: Who laughed? → A: Amy (Subject)

2. The house is very old.

   • Q: What is very old? → A: The house (Subject)

Tests to Identify the Subject

1. The Inversion Test

In a statement (declarative sentence), the Subject comes before the verb.

• Statement: James (S) is (V) at school.
  When we change it into a question (interrogative sentence), the Subject and verb switch places (invert).

• Question: Is (V) James (S) at school?

2. The Tag Question Test

A tag question is a short question added at the end of a statement. The Subject of the tag question refers back to the Subject of the main sentence.

• Example 1: Paul is getting big, isn’t he?

  • He refers back to Paul, so Paul is the Subject.

• Example 2: The children seem busy, don’t they?

  • They refers back to the children, so the children is the Subject.

This test also works for complex sentences:

• It was Paul who sent the note, wasn’t it?

  • Here, the Subject is it.

3. The Agreement Test

The Subject and verb must agree in number (singular/plural) in the present tense.

Singular Subject	Plural Subject
The dog barks.	The dogs bark.

However:

• Past tense verbs do not change with the Subject:

  • The dog barked. / The dogs barked.

• First-person (I, we) and second-person (you) Subjects use the same verb form:

  • I sleep. / We sleep.

This test works only for third-person Subjects (he, she, it, they, names, nouns) in the present tense.

Conclusion

By using "Who?" / "What?" questions, inversion, tag questions, and verb agreement, we can easily identify the Subject of a sentence.