Correct Answer: B

Rationale: The correct answer is B: 'The tests were graded by the teacher.' This sentence is an example of passive voice, where the subject receives the action. In passive voice construction, the focus is on the receiver of the action rather than the doer. Choices A, C, and D are not in passive voice. Choice A 'The teacher graded the tests' is in active voice where the subject (teacher) performs the action. Choice C 'The students took the test' is also in active voice with the subject (students) carrying out the action. Choice D 'The test was difficult' is in passive voice but does not exemplify the subject receiving an action performed by an agent, which is a defining characteristic of passive voice.

Correct Answer: C

Rationale: The sentence discusses evidence and clinical trials related to a specific therapy, indicating a scientific context. Scientific journal articles are known for presenting research findings, discussing evidence, and proposing further studies, making them the most suitable source for this type of information. Choices A, B, and D are incorrect because a motivational speech is more focused on inspiring and encouraging, a business memo typically deals with internal communication in organizations, and a personal blog reflects individual opinions or experiences, none of which align with the content and tone of the sentence provided.

Correct Answer: B

Rationale: The correct answer is 'B' - 'who.' 'Who' is the correct relative pronoun to introduce the clause 'who lives down the street,' providing more information about Mrs. Sato. The other choices, 'she,' 'which,' and 'whom,' are not appropriate relative pronouns for referring to a person in this context.

Correct Answer: A

Rationale: The correct order for the sentence 'yesterday she went to the store' is 'She went to the store yesterday.' In English, the standard word order for a sentence is subject-verb-object-adverbial (time). Choice A is the correct answer as it follows this standard order. Choice B changes the order of the subject and object. Choice C changes the order of the adverbial and subject. Choice D changes the order of the subject and adverbial. Therefore, choices B, C, and D are incorrect.

Correct Answer: B

Rationale: The correct definition of a homophone is a word that sounds the same as another word but has a different meaning and often different spelling. Choice A, 'Words with opposite meanings,' is incorrect as homophones do not necessarily have opposite meanings. Choice C, 'Synonyms,' is incorrect because homophones are not words with the same meaning. Choice D, 'Words with similar spellings,' is also incorrect as homophones may have different spellings.