Change the following sentence into a negative one:
This boy plays football.

Question

Change the following sentence into a negative one: 
This boy plays football.

Accepted Answer

To change a simple present tense affirmative sentence into a negative one, we use the auxiliary verbs "do not" or "does not" followed by the base form of the main verb.

Let's analyze the original sentence: "This boy plays football."
*   The subject is "This boy," which is a third-person singular subject.
*   The verb is "plays," which is in the simple present tense and takes the '-s' ending because the subject is third-person singular.

Now, let's evaluate each option:

**Justification for Option 3 (Correct Answer):**
**3. This boy does not play football.**
*   **Why it's correct:** For a third-person singular subject (like "This boy," "he," "she," "it," or a singular noun), the correct auxiliary verb for forming a negative sentence in the simple present tense is "does not."
*   When "does not" is used, the main verb reverts to its base form. So, "plays" becomes "play."
*   Therefore, "This boy does not play football" correctly follows the grammatical rules for forming a negative sentence in the simple present tense with a third-person singular subject.

**Explanation for why other options are incorrect:**

**1. This boy no plays football.**
*   **Why it's incorrect:** In English grammar, "no" is typically used as a determiner (e.g., "no money," "no time") or as an answer to a yes/no question. It is not used as an auxiliary verb to negate a main verb in this structure. To form a negative sentence in the simple present tense, an auxiliary verb like "do" or "does" is required before "not."

**2. This boy do not plays football.**
*   **Why it's incorrect:** This option has two errors:
    *   **Incorrect auxiliary verb:** For a third-person singular subject ("This boy"), the correct auxiliary verb for negation in the simple present tense is "does not," not "do not." "Do not" is used for subjects like "I," "you," "we," "they," or plural nouns.
    *   **Incorrect form of the main verb:** Even if "do not" were grammatically appropriate for the subject (which it isn't here), the main verb should be in its base form ("play"), not "plays." When "do" or "does" is used as an auxiliary, the main verb always takes its base form.

**4. This boy not plays football.**
*   **Why it's incorrect:** In the simple present tense, "not" cannot directly negate a main verb without an auxiliary verb. An auxiliary verb ("do" or "does") is essential to carry the tense and subject-verb agreement when forming a negative sentence. The structure "subject + not + verb" is grammatically incorrect for this tense.