The second part of the sentence tells us that the damage done to your body by smoking will stay with you forever. The correct answer is therefore “irreversible,” which means unable to be reversed, unable to be changed back. To provide further help, “implacable” means unstoppable, relentless; “irritable” means easily annoyed; “mollifying” means calming; “edible” means able to be eaten. 

We know that the hikers "travel[ed] twenty miles on foot in one day," so we can infer that they were tired after their hike. So, we need to pick out an answer choice that means something like "tired." "Energetic," then, cannot be the correct answer, because "energetic" means "showing or involving great activity or vitality," meaning that describing tired hikers as "energetic" would not make any sense. "Weary," however, is an adjective that means "feeling or showing tiredness, especially as a result of excessive exertion or lack of sleep," and because "weary" best describes the hikers' likely condition after hiking twenty miles in one day, "weary" is the correct answer.

This sentence contrasts something new ("smart phones") with something old ("flip phones"). Based on the location of the blank, you know that the answer choice has to relate to the old-fashioned nature of flip phones. This rules out "intrepid," which means adventurous; "innovative," which means pioneering or inventive; and "new-age," which means modern. The correct answer is “obsolete.” Something that is "obsolete" has been made irrelevant by some newer invention. To help you, "jocular" means good-natured and happy.

The idea here is that the container has been scrubbed, that is, turned from being "filthy," or very dirty, to "spotless," or very clean. So, we can infer that we need to pick out an answer choice that means something like very clean. So, that means that "dusty" cannot be the correct answer, as "dusty" means covered in dust and so is an antonym of very clean. The word that best fits the sentence is "immaculate," which means spotless, pristine, or free from error. As for the other answer choices, "hazardous" means dangerous, "content" means pleased or happy with circumstances as they stand, and "salubrious" means good for one's health.

We know that Tabitha "put no effort into [her paper]," so we can infer that she was "asked to rewrite" it because it was subpar. So, we need to pick out an adjective that means something like "subpar." "Lackluster," an adjective that means "lacking in vitality, force, or conviction; uninspired or uninspiring," is the correct answer because it is the answer choice that best describe's the paper that Tabitha "put not effort into."

We can infer that because Billy "passed his later tests with flying colors," we need to pick out an answer choice that is an adjective that means something like "later" to describe the exams for which he studied. So, neither "prior" nor "previous" can be the correct answer because both of those words are antonyms of "later." "Subsequent," however, means "coming after something in time; following," and because "subsequent" is the answer choice that best describes the tests for which Billy studied and best fits the context of the sentence, "subsequent" is the correct answer.

From the context of the sentence, you know that the blank word must mean something like “dangerous.” This should lead you to the correct answer, which is “perilous.” "Perilous" means very dangerous or ominous, as "peril" means danger. To help you, "benevolent" means good-natured and is an antonym of "malevolent" and "diabolical," which each mean evil; "obscure" means hidden or unusual. 

From the context of the sentence, you know that the blank word must describe some quality of Paul’s that makes him good at saving money. This information should lead you to the correct answer, which is “frugal.” "Frugal" means thrifty or economical with money. To help you, "philanthropic" means charitable, "susceptible" means vulnerable or in danger, and "magnanimous" means generous or noble.

In order to complete this sentence, one needs to find a word that describes the subject's neighbors and how they make the subject feel at home when he or she goes over to their house for dinner. The best word to describe the subject's neighbors is "hospitable." "Hospitable" means making guests feel welcome.

What do we know about substitute teacher described in the sentence? We know that he or she "reports students for breaking even the most minor rules." So, we could describe this substitute as being very harsh or severe. When we look for an answer choice that means something like "severe," it becomes apparent that "strict," a word that means harsh, severe, and focused on enforcing rules makes sense in the sentence and is the correct answer. The prefix "stri-" means binding, tight, or fixed, as seen in the words “restrictive,” “strict,” and “constrict.” None of the other answer choices make sense in the blank: “accessible” means able to be accessed; “introspective” means focused on internal thoughts; “somnambulant” means sleep-walking; and “charitable” means generous in giving things to others.