Subject–Verb Agreement and Tense in a Lab Report
A student writes this draft paragraph for a science report:
'The results of the experiment was surprising. Each of the samples were heated to 80°C. Neither the acid nor the base react at room temperature, but when they were mixed, a gas were produced. The data shows that temperature effect the reaction rate. The team, who is working late, has repeated the trial three times.'
Her teacher marks four errors: two subject–verb agreement errors, one tense inconsistency, and one error involving a collective/relative-clause subject. The student must revise the paragraph so every verb agrees with its true subject and the tense is consistent.
1. Identify the subject–verb agreement errors and correct them, naming the true subject in each case.
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(1) 'The results ... was surprising' → were. The subject is 'results' (plural), not 'experiment'; 'of the experiment' is a prepositional phrase.
(2) 'Each of the samples were heated' → was. 'Each' is singular and takes a singular verb, even though 'samples' is plural.
(3) 'a gas were produced' → was produced. The subject is 'a gas' (singular).
(4) 'temperature effect the reaction rate' → affects (verb, not noun 'effect', and singular subject 'temperature').
2. Fix the tense inconsistency and the 'neither...nor' and relative-clause constructions, explaining the rule for each.
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Tense: 'Neither the acid nor the base react ... but when they were mixed' mixes present and past. Choose one frame - e.g., past throughout: 'Neither the acid nor the base reacted at room temperature, but when they were mixed, a gas was produced.'
Neither...nor: the verb agrees with the nearer subject. 'Neither the acid nor the base' → nearer subject 'base' (singular) → 'reacts' (present) or 'reacted' (past).
Relative clause: 'The team, who is working late, has repeated...' - 'team' as a unit takes a singular verb ('has'), which is correct, but the relative pronoun should match: use 'which' or 'that' for a collective unit, or if treating members individually, 'who are working'. Keep it consistent: 'The team, which is working late, has repeated the trial three times.'
3. Rewrite the whole paragraph correctly in one consistent tense.
Read the worked answer
Model revision (past tense, consistent):
'The results of the experiment were surprising. Each of the samples was heated to 80°C. Neither the acid nor the base reacted at room temperature, but when they were mixed, a gas was produced. The data showed that temperature affects the reaction rate. The team, which was working late, had repeated the trial three times.'
(General truths such as 'temperature affects the rate' may stay in the present even inside a past narrative - that is an accepted exception, not an inconsistency.)