This question tests verb tense sequencing with past perfect. The sentence uses "had compared" (past perfect) to show an action completed before another past action, so we need simple past tense "awarded" for the subsequent action. The timeline is: first the committee compared (past perfect), then it awarded (simple past). Choice A ("awards") uses present tense which doesn't fit the past context, Choice B ("has awarded") uses present perfect which conflicts with "Last month," and Choice D ("will award") uses future tense which contradicts the past time frame. When you see past perfect ("had" + past participle), the next action in sequence typically uses simple past tense.

This question tests pronoun reference to a singular antecedent. The pronoun must refer back to "the second version" (singular), so we need the singular pronoun "it." The sentence indicates that readers found the second version unclear. Choice B ("they") is plural, Choice C ("them") is plural and objective case when we need subjective, and Choice D ("their") is possessive when we need a subject pronoun. When tracking pronoun reference, identify the specific noun the pronoun replaces and ensure they match in number.

This question tests subject-verb agreement with a compound subject. The subject of the sentence is "The series of experiments, along with detailed notes from each operator," but the true grammatical subject is just "series" (singular) because "along with detailed notes" is a parenthetical phrase that doesn't affect the verb number. Since "series" is singular and the action occurred in the past ("later used"), we need the singular past tense verb "was." Choice A ("were") incorrectly treats the subject as plural, Choice C ("are") uses present tense when past is needed, and Choice D ("have been") creates an awkward tense that doesn't match the simple past context. When determining subject-verb agreement, always identify the core subject and ignore interrupting phrases introduced by "along with," "as well as," or "in addition to."

This question tests the past perfect tense to show completed action before another past event. The timeline shows that by 2019 when the follow-up began, the researchers had already completed their review of the 2015 data, so we need past perfect "had reviewed." Choice A ("review") is present tense, Choice B ("reviewed") is simple past but doesn't show the completion before the follow-up, and Choice D ("will have reviewed") is future perfect which doesn't fit the past context. Use past perfect ("had" + past participle) when one past action was completed before another past action began.

This question tests subject-verb agreement with subjects modified by prepositional phrases. The subject is "Trees" (plural), and the phrase "near busy roads" is just a modifier that doesn't affect the verb number. The phrase "in addition to lowering heat" is also parenthetical. Since "Trees" is plural and the sentence describes a general fact, we need the plural present tense "help." Choice A ("helps") is singular, Choice C ("helped") is past tense when present is needed for general facts, and Choice D ("has helped") is singular. Always identify the true subject by removing prepositional phrases and parenthetical elements.

This question tests subject-verb agreement and verb tense. The subject "the aquifer" is singular, and the present tense context (general scientific fact about how aquifers behave) requires "does not refill." Choice B ("do not refill") has a plural verb for a singular subject, Choice C ("did not refill") uses past tense for a general truth, and Choice D ("have not refilled") uses present perfect which doesn't fit the context of explaining a general principle. Scientific explanations about how things generally work use simple present tense.

This question tests pronoun case after a verb. The supervisor is asking about the subject who performed the action, so we need the subjective case "we." The pronoun serves as the subject of "had followed." Choice B ("us") is objective case, Choice C ("our") is possessive, and Choice D ("ours") is possessive pronoun—none can serve as the subject of a verb. When choosing pronouns, determine whether they're performing the action (subjective: I, we, he, she, they) or receiving it (objective: me, us, him, her, them).

This question tests pronoun case with compound objects of a preposition. After the preposition "to," we need the objective case "me," not the subjective "I." The compound object is "Jordan or me." Choice A ("I") is subjective case but we need objective after a preposition, Choice C ("myself") is reflexive and inappropriate here since the subject isn't "I," and Choice D ("mine") is possessive. A quick test: remove "Jordan or" and see what sounds right—"email questions to me" not "email questions to I."

This question tests subject-verb agreement with contrasting elements. The subject is "The coins" (plural), and the phrase "not the catalog" doesn't change this—it's a contrasting element set off by commas. Since "coins" is plural and the action is in the past, we need the plural past tense verb "were." Choice A ("is") is singular present, Choice B ("was") is singular past, and Choice D ("has been") is singular present perfect—all incorrect for a plural subject. When you see "X, not Y" constructions, the verb agrees with X, not Y.

This question tests subject-verb agreement with compound subjects. The subject is "The speed of the waves, along with the density of the medium," but the core subject is just "speed" (singular) because "along with the density" is a parenthetical addition. Therefore, we need the singular verb "determines." Choice A ("determine") is plural, Choice C ("have determined") is plural and past tense, and Choice D ("are determining") is plural and progressive. Remember that phrases beginning with "along with," "together with," or "as well as" don't make a singular subject plural.