Also in 2025 Practice Test B English, question 49.
Passage The End of an Era
The End of an Era
(1) In 2004, the National Aeronautics and Space Administration (NASA) landed a rover, or robotic vehicle, named Opportunity on the surface of Mars. (2) The rover’s mission was to search for evidence of water and life on the planet. (3) The rover was designed to gather data on Mars for about 90 days, but Opportunity’s assignment did not come to an end until nearly 15 years later in 2019.
(4) During the rover’s mission, a high-resolution camera on the rover’s robotic arm took magnified photographs of the surface of Mars. (5) The photographs revealed small round rocks scattered across the surface of the planet. (6) The scientists nicknamed these rocks “blueberries” based on the rocks’ resemblance to the fruit. (7) These rocks were important because their spherical shape suggested that liquid water may have flowed over them for a substantial amount of time.
(8) Opportunity continued to provide valuable data about craters and other surface features. (9) Throughout the mission, the rover traveled a total of 28.06 miles across Mars’ surface. (10) When Opportunity had traveled nearly the length of a marathon, scientists celebrated the accomplishment by naming the valley that the rover was in Marathon Valley. (11) However, in 2018, a dust storm spread all over the planet, putting the rover’s progress on hold.
(12) Prior to this planet-wide dust storm, minor dust storms had periodically deposited a layer of dust onto the solar panels of the rover. (13) These prevented it from charging its batteries. (14) Scientists then had to rely on the passing winds and dust devils to clean off the solar panels. (15) After the massive 2018 dust storm subsided, scientists expected to be able to reestablish communication with Opportunity. (16) They made repeated attempts but to no avail. (17) In 2019, NASA finally declared Opportunity’s mission complete.
(18) Opportunity was an important asset in scientists’ study of Mars; it returned valuable data about our neighbor planet and survived powerful dust storms. (19) NASA described the mission of Opportunity as “one of the most successful and enduring feats of interplanetary exploration.” (20) Even though this rover’s journey ended, other rovers still roam the surface of Mars.
Question
Which sentence should follow sentence 3 to best introduce the topic of the passage?
- ADespite the challenges of operating on the surface of another planet, the Opportunity rover made many valuable contributions to the field of space research.
- BThe Opportunity rover mission was a success because it informed NASA scientists about how water might have existed on Mars.
- CThroughout the historic mission of the Opportunity rover, NASA scientists had to overcome challenges created by the flaws in the rover’s design.
- DThe Opportunity rover mission surpassed the original timeline of the assignment and allowed scientists to collect additional data about the planet Mars.
Show the answer
Correct answer: A
The question asks for the sentence that should follow sentence 3 to best introduce the topic of the passage.
A. CORRECT. This sentence best introduces the passage’s topic: the Opportunity rover had many accomplishments on its mission, despite numerous challenges. Some of those accomplishments include providing high-resolution photographs (paragraph 2), traveling long distances (paragraph 3), and providing data about craters and other surface features (paragraph 3).
B. Incorrect. Although paragraph 2 discusses how photographs taken by the rover showed rocks that may have been shaped by water, this idea alone is not the topic of the entire passage.
C. Incorrect. While this sentence incorporates ideas about difficulties the scientists encountered because of the Opportunity rover’s design (paragraph 4), the main topic of the passage is not the design flaws and obstacles scientists encountered throughout the mission. The passage primarily focuses on the achievements of the mission.
D. Incorrect. While it is true that the Opportunity rover mission lasted much longer than planned (sentence 3), this fact is a supporting detail of the passage, not the main topic of the passage; surpassing the original timeline is only one of the rover’s many achievements mentioned in the passage.
Question analysis
This revising question works with “The End of an Era,” a passage about NASA's Opportunity rover on Mars, and asks which sentence should follow sentence 3 to best introduce the topic. Students must keep the whole passage in view, from the rover's photographs and travels to the dust storms that ended its mission, and judge which choice previews it best.
- NYS standards
- 7W2a introducing and organizing a topic
- Grade level
- Grade 7 reading and task
- Compared with grade 7
- At grade 7 Choosing a sentence that introduces a passage's topic is a standard grade 7 writing task. The passage is twenty plain sentences about one rover mission, and every choice draws on that mission, so it calls for a typical careful comparison.
- Estimated difficulty
- Moderate: several steps, or a close reading with one strong distractor.
- Thinking it demands
- Depth of knowledge 2, skills and concepts · mainly evaluate
- What makes it hard
- Evidence in several places moderate
- How sentences fit together minor
- Evidence
- Answered from the whole text
- Reading level
- Passage: about grade 11, 337 words; question and choices: about grade 14, 101 words.
- Students, last 30 days
- Not enough answers yet to show (it takes 10).
Why it is hard, traps and wrong answers (shows the answer)
Why it is hard
Sentence 3 already tells a striking story, a 90-day mission that lasted nearly fifteen years, and the most tempting continuation simply repeats it in new words. The other near misses each pick one part of the passage, the water evidence or the dust problems, and make it the whole. The question rewards skimming every paragraph first and choosing the sentence that covers both the achievements and the hardships, the pairing the final paragraph makes.
Evidence in several places moderate Working it out
The topic only emerges from the later paragraphs: the “blueberries” of sentences 4–7, the 28.06 miles of paragraph 3, the dust storms of paragraph 4 and NASA’s praise in sentence 19. (Kirsch & Mosenthal, 1990; Gorin & Embretson, 2006)
How sentences fit together minor Working it out
The new sentence follows sentence 3’s surprise that a 90-day mission lasted nearly 15 years, so it must turn from that fact to what the mission achieved. (Halliday & Hasan, 1976)
Strategy: Skim the opening sentence of each later paragraph to see what the passage covers, then ask which choice would prepare a reader for all of it.
Traps
- Too narrow: A single detail offered as the central idea or a summary, or a summary that keeps minor details and leaves out an essential part.
- Says it twice: Repeats an idea that the sentence or passage already states.
- Off the point: Adds or keeps something that does not support the paragraph's or the passage's focus, or an introduction or conclusion that misses the main point.
The wrong answers, classified
B Too narrow (King et al., 2004)
Picks the water finding of paragraph 2, a real result, but it covers one paragraph and leaves out the rover’s travels, its endurance and the dust storms.
C Off the point (Halliday & Hasan, 1976)
Builds on the dust that blocked the solar panels in paragraph 4, but the passage never blames flaws in the rover’s design and dwells on its achievements.
D Says it twice (Connors & Lunsford, 1988)
Follows sentence 3 smoothly, but saying the mission “surpassed the original timeline” only restates the 90 days that became 15 years instead of introducing what comes next.
Working it out, step by step
Figure out what the question asks
This revising question asks for a sentence to add after sentence 3. It should introduce the topic of the whole passage. A good introduction gives a preview, a quick look at everything coming. It doesn’t repeat one fact or zoom in on one part. For example, a report on a soccer season might begin: The team lost two stars but still won the title. That previews both the struggles and the wins.
Skim each paragraph
- Paragraph 2 (sentences 4–7): The rover’s camera found small round rocks that hinted at water.
- Paragraph 3 (sentences 8–11): It sent data and traveled 28.06 miles. Then a huge dust storm stopped it.
- Paragraph 4 (sentences 12–17): Dust had covered its solar panels before. After the 2018 storm, NASA could not reach it.
- Paragraph 5 (sentences 18–20): It “returned valuable data about our neighbor planet and survived powerful dust storms.”
Name the topic
So the passage covers two things. One is what the rover achieved: photos, data and miles. The other is its challenges, mainly the dust storms. Challenges are hard problems. Sentence 18 puts both together. The new sentence should preview both.
Check each choice
- A is right. It names the challenges and the “many valuable contributions.” That covers the whole passage.
- B is wrong. Water is only paragraph 2. It leaves out the travel and the dust storms.
- C is wrong. The passage never blames flaws in the rover’s design. It mostly praises the rover.
- D is wrong. Sentence 3 already says the mission lasted far past 90 days. D repeats it instead of looking ahead.
Watch out: D follows sentence 3 smoothly, so it sounds right. But it only restates sentence 3 in new words.
Choose the answer
So the answer is A: “Despite the challenges of operating on the surface of another planet, the Opportunity rover made many valuable contributions to the field of space research.”
Why this answer and not the closest wrong one
D is the closest wrong answer, because it flows right after sentence 3. But it only repeats that the mission lasted longer than planned. A previews both halves of the passage: the rover’s achievements and the challenges it survived. Sentence 18 sums up the same two ideas.
More questions like this
The original DOE question
The passage “The End of an Era” as printed (page 60)
