Question 32·Medium·Text Structure and Purpose
Environmental economists often argue that increasing gasoline taxes is the most effective way to reduce carbon emissions from cars, because higher prices motivate drivers to choose more efficient vehicles or travel less. Yet this policy tool tends to burden low-income commuters who have limited access to public transportation. For that reason, some researchers propose a refundable carbon tax that returns revenue to households as cash dividends.
Which choice best describes the function of the underlined sentence?
For SAT questions asking about the function of a sentence, always read at least one sentence before and after it, then describe in your own words what that sentence is doing (for example: adding an example, contrasting with a claim, explaining a process, showing a consequence, or introducing a new topic). Pay close attention to transition words like “yet,” “however,” “for example,” or “therefore,” since they signal whether the sentence supports, contrasts, or concludes. After you’ve named its role in simple terms, eliminate answer choices whose descriptions clearly don’t match that role (like “historical example” when there is no specific event), and choose the one that best captures the sentence’s function in the argument, not just shared vocabulary words.
Hints
Look at what comes before and after
Reread the sentence before the underlined portion and the sentence after it. Ask yourself: how does the underlined sentence connect these two ideas?
Pay attention to the transition word
Notice that the underlined sentence starts with the word “Yet.” Does this word usually signal agreement, explanation, or contrast with what came just before?
Ask what kind of information is added
Ask: Is the underlined sentence mainly giving an example, explaining how the policy works, raising an issue about who is affected, or changing the subject to something else?
Match function, not topic words
Several choices repeat familiar words (like “public transportation” or “gasoline taxes”). Instead of matching words, decide what the sentence is doing in the argument and pick the choice that best describes that role.
Step-by-step Explanation
Understand the surrounding context
First, read the sentence before and after the underlined portion.
- The first sentence says that increasing gasoline taxes is “the most effective way” to reduce emissions.
- The underlined sentence begins with “Yet” and says this policy “tends to burden low-income commuters who have limited access to public transportation.”
- The following sentence explains that because of this, some researchers propose a refundable carbon tax.
So the underlined sentence is part of a contrast with the earlier praise of gasoline taxes and helps explain why an alternative is being proposed.
Identify what the underlined sentence is doing
Focus on what new idea the underlined sentence adds:
- It does not give a past event or story; it makes a general statement.
- It does not explain in detail how higher gas taxes cut emissions (that is already stated: higher prices make people drive less or choose efficient cars).
- Instead, it introduces who is harmed by the policy: low-income commuters with poor transit options.
So its main role is to point out a problem or limitation of the policy that was just called very effective.
Eliminate answer choices that do not match that role
Now compare each option to what the sentence actually does:
- Choice A: “It provides a historical example…” — The sentence is not about a specific time, place, or event; it is a general statement, not a historical example. So A does not fit.
- Choice C: “It elaborates on the mechanism through which gasoline taxes reduce emissions.” — The mechanism (higher prices → different choices) was already described in the first sentence. The underlined sentence talks about which people are burdened, not how emissions fall. So C is wrong.
- Choice D: “It introduces a new unrelated topic concerning public transportation infrastructure.” — The sentence still discusses “this policy tool” (gasoline taxes) and connects it to public transportation only to show how some commuters are affected. It stays on the same overall topic, so D is incorrect.
We have eliminated A, C, and D.
Match the remaining description to the sentence’s function
The remaining option says that the sentence qualifies the claim by acknowledging a potential drawback of the proposed policy. This matches our analysis: the earlier claim that gasoline taxes are very effective is limited by the reminder that they “tend to burden low-income commuters.” Therefore, the correct answer is: It qualifies the claim by acknowledging a potential drawback of the proposed policy.