Short version: grammar questions don't announce themselves. Look at what changes across the four choices (a verb, a pronoun, an intro phrase, a list) and that tells you which rule is in play and which trap to watch for. Start with the decoder below.
The decoder: what changes tells you the rule
Before hunting for an answer, look at how the four choices differ. That difference names the game.
| What changes in the choices | The rule | Your first move |
|---|---|---|
| A verb (is / are, runs / run) | Subject-verb agreement | Find the one true subject. |
| A pronoun (its / their, he / they) | Pronoun agreement or ambiguity | Find the one true antecedent. |
| A long intro phrase + comma | Modifier placement | Run the who/what test. |
| A list or a comparison | Parallel structure | Match the items' form. |
| Only the verb's tense | Verb tense | Match the passage's timeline. |
| Only the punctuation | Sentence boundaries | Hunt for the comma splice. (punctuation sheet) |
Subject-verb agreement
The move: cross out everything between the subject and the verb, then check the match.
- Ignore prepositional phrases and asides: The box of old ornaments sits (not sit) on the shelf.
- Collective nouns (team, family, committee) are singular.
- Indefinite pronouns (each, every, everyone, neither, either) are singular.
- With neither/nor and either/or, the verb matches the closest subject.
Pronouns
| Rule | What to check |
|---|---|
| Agreement | A pronoun matches its noun in number. A singular company takes its, not their. |
| Ambiguity | If a pronoun could point to two nouns, replace it with the specific noun. |
| its vs. it's | it's = "it is." its = possessive. Always. |
| their / they're / there | possessive / "they are" / a place. The test swaps these on purpose. |
Modifiers
The rule: an opening phrase describes the noun right after the comma.
- Dangling modifier = that noun is wrong or missing: "After hiking for hours, the summit came into view." The summit didn't hike.
- Fix: ask "who did the action?" and put that noun right after the comma: "After hiking for hours, we saw the summit."
Parallel structure
| Situation | The rule |
|---|---|
| Lists | Every item wears the same grammatical form: hiring, investing, and overhauling. |
| not only… but also | Whatever follows not only matches whatever follows but also. |
| Comparisons | Compare like things: "than those of the sales team," not "than the sales team." |
Verb tense
Keep tense consistent with the timeline the passage has already established. Don't shift from past to present without a reason in the sentence. When only the tense changes across the choices, the answer is the one that matches the verbs around it.
The traps the test repeats
| Trap | The fix |
|---|---|
| Verb agrees with the nearest noun | It agrees with the subject, which the test hides behind phrases. Cross them out. |
| "their" for a singular noun | A company, team, or committee is singular: its. |
| Ambiguous he / they / it | Name the noun instead of the pronoun. |
| Dangling modifier | Put the real subject right after the opening comma. |
| Faulty parallelism / illogical comparison | Match the forms; compare like to like. |
None of these reward instinct. They reward a fast diagnosis and the right tool, which is why they are among the most recoverable points on the test once you drill them. Forge can show you whether grammar is a steady strength or a quiet leak, and which specific rule keeps catching you, so your practice goes to the one actually costing you points instead of all of them at once.