Since Heidi was parched at the end of the hike, this indicates that she drank too little on the hike.  During the hike, she tried to quench or satisfy her thirst, but she could not with the amount of water she brought with her.

Be careful with that, do not mar the surface! Whenever something is marred, it is scratched up or broken.

She is strong, she will not falter. Faltering refers to failing or becoming unsteady. Someone who is strong, is unlikely to falter (at least at most physical tasks).

Though the other choices do make sense, they would only be found in very specific contexts. While the use of "falter" would be the most common choice to fill in the blank.

I hope this heavy pack doesn't encumber you too much. Encumber most nearly means burden or weigh-down. A heavy pack is very likely to encumber someone.

We know from the sentence's context that George did not expect any rain because of the incorrect weather report, so we need to pick out a verb that means something like "expect." While "see" might look like a correct answer, a sudden downpour occurred and George was drenched, so we can reasonably conclude that George saw rain. "Anticipate," however, is a verb that can mean "regard as probable; expect or predict" or "guess or be aware of what will happen and take action in order to be prepared." Since "anticipate" is the answer choice closest in meaning to "expect" and best fits the sentence, "anticipate" is the correct answer.

The dragons "want nothing more than to . . . collect [treasure] into huge piles in secret caves" and protect that treasure, so we need to pick out an answer choice that means something like "gather up a large amount of to keep and protect." Neither "spend" nor "donate" can be the correct answer, then, because both "spend" and "donate" are antonyms of "gather up to keep," and neither would make sense in the context of the sentence, as the dragons are clearly not spending or donating their treasure. "Hoard," however, when used as a verb, can mean "amass (money or valued objects) and hide or store away," and because "hoard" best describes the dragons' collecting and guarding of treasure, "hoard" is the correct answer.

We can infer from the sentence that we need to pick out a verb that means something like "deserved," because we know that "[Drew's] classmates didn't think the slight interruption deserved one either." "Warranted," a verb that means "justified or necessitated (a certain course of action)," is the answer choice that best fits the context of the sentence, so "warranted" is the correct answer.

We can infer that after disagreeing about which type of candy to buy with their money, the boys came to an agreement "so they both would be happy." So, we need to pick out a verb that means something like "come to an agreement." "Disagreed" might looked like a potentially correct answer because the boys initially disagreed about what type of candy to buy, but "disagreed" would not make sense as a verb describing the resolution to the boys' problem, so it cannot be the correct answer. "Compromised," however, is a verb that means "settled a dispute by mutual concession," and because "compromised" best describes how John and Jim reached an agreement, "compromised" is the correct answer.

We know that "the ice [on the pond] broke and several skaters nearly fell into the icy water," so we can infer that the city banned skating on the pond "[f]or its citizens' safety." So, we need to pick out a verb that means something like "banned." So, that means that neither "permitted" nor "advised" can be the correct answer, because each of those verbs would suggest that the city either allowed people to skate on the pond ("permitted") or wanted them to skate on the pond ("advised"), neither of which is the case. "Proscribed," however, is a verb that means "forbid, especially by law" or "denounced or condemned," and because "proscribed" best describes what the city did about the skating taking place on the frozen pond after the ice broke, "proscribed" is the correct answer.

We can infer that because the sentence is describing "gemstones, coins, and jewelry" that are sitting "in the moonlight," that these items are glistening or sparkling. So, we need to pick out a verb that means something like "glistened" or "sparkled." Neither "twitched" nor "moved" can be the correct answer, then, because each of those answer choices would suggest that the "gemstones, coins, and jewelry" are moving, which is unlikely. "Twinkled," however, is a verb that can mean "shine with a gleam that varies repeatedly between bright and faint" when referring to a star, light, or a shiny object, and because "twinkled" best describes what the treasure did in the moonlight, "twinkled" is the correct answer.