Correct Answer: C

Rationale: The word 'otherwise' is used to indicate that although the patients are resting comfortably, under different circumstances, bed checks should still be done every half hour. This maintains the correct logic and flow of the sentence, making it grammatically correct. Choice A, 'despite,' would imply a contrasting situation that is not the intended meaning in this context. Choice B, 'however,' also implies a contrast rather than the intended conditional relationship. Choice D, 'afterward,' indicates a time sequence that does not fit the context of the sentence.

Correct Answer: B

Rationale: The word 'envelope' is used incorrectly in the sentence. The correct word should be 'folder,' as mentioned in the original sentence. An envelope is a flat paper container for a letter or documents, while a folder is a folded cover for papers or documents. 'Give,' 'whoever,' and 'replies' are all used appropriately in the sentence, so they are not the incorrect words.

Correct Answer: B

Rationale: The correct answer is 'itself.' The sentence is referring to the centrifuge, which is an object, not a person. Therefore, the word 'itself' is used to indicate that the centrifuge cannot run on its own; it requires constant attention. Choices A, C, and D are incorrect because they refer to a person or people, which is not suitable in the context of the sentence.

Correct Answer: C

Rationale: In the given sentence, the word 'effect' is used incorrectly. In this context, the word 'affect' should be used instead of 'effect.' 'Affect' is a verb that means to influence or have an impact on something, while 'effect' is a noun that represents the result or outcome of an action. Therefore, to convey the intended meaning that her mentor's advice was bound to influence or impact her final decision, the correct word should be 'affect,' not 'effect.' The other options ('mentor's,' 'advice,' 'decision') are used appropriately in the sentence and do not contain any errors.

Correct Answer: D

Rationale: The correct phrase to use in this sentence is 'will listen and learn' because it indicates actions that will take place in the future. The verb 'will' is needed to show that these actions have not occurred yet but are planned for the upcoming months. Choices A, B, and C are incorrect because they do not convey the future tense required in the sentence. Choice A lacks the future tense, choice B is in the present continuous tense, and choice C is in the past perfect tense, which are all grammatically incorrect in this context.