Based on visible checker behavior
A rule explanation is a decision aid, not a rewrite verdict
The checker marks a change in the sentence, proposes a correction, and gives a concise reason. That sequence helps you check whether the suggested form matches your intended meaning. A red underline alone tells you that something changed; it does not tell you which pattern to avoid next time.
Not the same as a full language lesson or an academic editor.
In short
Correct the sentence and name the pattern.
Compared with a spelling-only pass, this workflow keeps the correction, the relevant sentence, and the short reason together. That makes the next action clear: accept, reject, or revise the suggestion against your meaning.
- Best for
- ESL emails, essays, cover letters, and any repeated grammar mistake you want to understand.
- Not ideal for
- Legal, medical, or subject-matter review; grading; and writing tasks that need a full pedagogical explanation.
- Fails when
- The source sentence is ambiguous or missing context. Add the surrounding sentence before deciding whether to apply a fix.
See the difference
Two small examples of the correction-plus-rule format. Check the rule against the meaning you intended.
Terms the checker helps separate
- Subject-verb agreement
- The verb matches the true subject of the sentence, even when another noun is closer to it.
- Verb form
- The form following an auxiliary such as “will” follows the grammar pattern required by that auxiliary.
- Punctuation
- Marks such as commas and apostrophes clarify sentence boundaries and ownership; they do not replace a grammar check.
- Word choice
- A grammatically valid word can still be the wrong word for the intended meaning, so review the suggestion in context.
Open the full Grammar Checker to test a real sentence.