Grammar: The One-Error Rule and the Temptation to Over-Correct
Ken has written a 140-word paragraph about his school festival and must correct it under a strict rule: five sentences are underlined, but only some contain an error, and correct sentences must be left exactly as written. Each unnecessary change loses a point. The underlined sentences are: (1) 'The number of visitors to the festival were larger than last year.' (2) 'The gym, which we decorated on Friday, was used for the concert.' (3) 'Walking into the hall, the decorations surprised the guests.' (4) 'Neither the teachers nor the principal was told about the change.' (5) 'Our teacher said that the concert had finished before the guests arrived.' Ken's partner proposes four changes: 'were' to 'was' in (1); 'which' to 'that' in (2); 'was' to 'were' in (4); 'had finished' to 'has finished' in (5).
1. Which of the partner's four proposals should Ken accept, and which should he reject? Justify each with a rule.
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Accept one only: 'were' → 'was' in (1). The subject is 'the number', which is singular, even though the plural 'visitors' sits immediately before the verb. Compare 'a number of visitors were' (plural) with 'the number of visitors was' (singular); the definite article plus 'number of' is the singular pattern. Reject the rest. (2) The clause after the comma is non-restrictive, so 'which' is required and 'that' would be an error - a change here creates a mistake. (4) With 'neither ... nor', the verb agrees with the nearer subject, 'the principal', which is singular, so 'was' is correct; the partner's 'were' would be wrong. (5) 'Had finished' is past perfect, and it is justified because the finishing happened before the saying; 'has finished' would blur that sequence and is not required by anything in the sentence. The scoring rule is the real lesson: in a one-error-per-sentence task, an unnecessary edit is scored as a wrong answer, so a candidate who 'improves' correct sentences loses marks for understanding grammar well but not instructions.
2. Sentence (3) genuinely needs repair. Give two rewrites that keep the meaning, and state the rule that makes the original wrong.
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The original makes 'the decorations' the thing that walked into the hall. Rule: an introductory participle phrase is understood to describe the subject of the main clause, so that subject must be the doer of the action in the participle. Fix 1, keeping the participle: 'Walking into the hall, the guests were surprised by the decorations.' Fix 2, keeping 'the decorations' as subject and supplying a subject for the participle: 'When the guests walked into the hall, the decorations surprised them.' Fix 1 is shorter and keeps the sentence's original shape, so it is usually the better exam answer; fix 2 is useful when the writer wants to keep the emphasis on the decorations. Do not 'fix' it by writing 'Walking into the hall, the decorations were surprising', which leaves the same dangling participle with a different adjective. Choose the version that changes the fewest words while restoring the correct doer.
3. After changing 'were' to 'was' in (1), the sentence reads 'The number of visitors to the festival was larger than last year.' Is anything still loose? How should Ken decide whether to touch it?
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Yes: strictly, a number is compared with another number, not with a year, so 'was larger than last year's' or 'was larger than in the previous year' is tighter. But the agreement error is the one the item is testing, and the instruction allows one edit per sentence. The judgement is about instructions rather than grammar: if the task says 'correct the error', change the verb only. If the task says 'rewrite the sentence so that it is correct and natural', fix the comparison as well. Recognising a second, smaller imperfection without acting on it is a skill in itself - it stops the candidate from making an unlicensed change while still showing that the sentence has been understood. A quick test: ask which error a marker could point to with a named rule. Agreement has a rule; the loose comparison has a preference.