Correct Answer: C

Rationale: The correct answer is 'C: I was mowing the lawn.' This sentence correctly uses the past continuous tense to indicate an action that was in progress at a specific time in the past when the thunderstorm started. Choice A 'I mowed the lawn' is in simple past tense, not past continuous, and does not convey the ongoing nature of the action. Choice B 'I am mowing the lawn' is in present continuous tense, not past continuous, and does not match the past timeframe. Choice D 'I have mowed the lawn' is in present perfect tense, not past continuous, and does not convey the ongoing action at a specific past time.

Correct Answer: B

Rationale: The correct usage of 'affect' in a sentence is as a verb meaning to influence something, as in 'The weather will affect our plans.' Choice A is incorrect because 'affect' should be 'effect,' which is a noun representing the result of an action. Choice C is incorrect as 'affect' should be 'effect' to describe a disorder. Choice D is incorrect because 'affect' should be 'effect' to convey the result of the news.

Correct Answer: A

Rationale: Option A uses correct punctuation by correctly utilizing the semicolon to separate two closely related independent clauses. This punctuation choice effectively conveys the relationship between the two ideas presented in the sentence. Choice B is incorrect because it uses a comma without a coordinating conjunction to join two independent clauses. Choice C is incorrect as it lacks the coordinating conjunction 'and' after the comma to connect the two independent clauses. Choice D is incorrect because it lacks any punctuation or conjunction to properly separate the two independent clauses, leading to a run-on sentence.

Correct Answer: A

Rationale: The correct answer is 'Slang.' Slang refers to informal words or phrases that are specific to a particular group of people, such as young people or a specific culture. In this scenario, the teacher is hearing non-standard words and expressions used by students, which aligns with the definition of slang. Jargon typically refers to specialized terminology used within a specific profession or group. Dialect refers to a particular form of a language that is specific to a region or social group. Vernacular refers to the everyday language spoken by people in a particular region or country.

Correct Answer: D

Rationale: The comma after 'delicious' is unnecessary as it separates the adjective 'delicious' from the noun 'stew'. In this case, 'delicious' is describing the type of stew, so the comma should be removed to maintain correct sentence structure. The other commas in the sentence are correctly used to separate items in a list and after introductory phrases, making them necessary for clarity and grammatical correctness.