Find the one underlined portion of a sentence that breaks a grammar rule — or confirm there's no error at all. Most students know the rules; the skill being tested is spotting the breach at reading speed. Every question comes with a written explanation of exactly which rule was broken.
One underlined portion is usually just awkward, not wrong. Check each candidate against an actual rule before committing — "sounds off" isn't evidence.
When a prepositional phrase sits between the subject and verb, it's easy to agree the verb with the nearest noun instead of the real subject.
"No error" is a real answer choice on plenty of exams. If nothing you check breaks a specific rule, that's the answer — don't invent a problem.
Straight from the bank — one per difficulty tier. Reveal the answer to see the explanation you'd get in a real session.
The collection of rare coins are kept in a locked case at the museum. Which underlined portion contains an error?
B — are. The subject is collection (singular), not coins — the prepositional phrase "of rare coins" doesn't change that. The verb should be is, so are is the error. In and at are both used correctly as prepositions.
By the time the guests arrived, she has already finished cooking and set the table. Which underlined portion contains an error?
B — has already finished. "By the time the guests arrived" establishes a past event that happened before another past event — that calls for the past perfect, had already finished, not the present perfect has already finished. The other underlined verbs are correctly formed.
Neither the coach nor the players was aware that the rules had changed. Which underlined portion contains an error?
C — was. With neither...nor, the verb agrees with the closer subject — here, the plural players — so the verb should be were, not was. This is the advanced-tier version of the agreement trap: the error sits in the verb, not in either noun.
Error identification is the subtopic where knowing the rule and applying it fast are two different skills — practice closes that gap.
For every item, state which specific rule was broken before moving on. Untimed practice is where you build a mental checklist you'll run automatically later.
Move to timed sessions once you can name rules on sight. Error identification runs longer than vocabulary items since there's a full sentence to scan.
Combine error identification with sentence completion in a mock — both test structural control over a full sentence.
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