Question
What is the best way to combine the sentences?
(1) Scientists now believe that Jupiter may have as many as seventy-nine moons.
(2) One of Jupiter’s moons is named Io.
(3) Io has the greatest number of active volcanoes in the solar system.
- AIo, which is one of Jupiter’s moons, has the greatest number of active volcanoes in the solar system, and scientists now believe that Jupiter may have as many as seventy-nine moons.
- BScientists now believe that Jupiter may have as many as seventy-nine moons, and one of them is named Io, which has the greatest number of active volcanoes in the solar system.
- CScientists now believe that Jupiter may have as many as seventy-nine moons, including one named Io, which has the greatest number of active volcanoes in the solar system.
- DIo, a moon with the greatest number of active volcanoes in the solar system, is one of Jupiter’s moons, and scientists now believe that Jupiter may have as many as seventy-nine moons.
Show the answer
Correct answer: C
The question asks for the best way to combine the sentences.
A. Incorrect. Although the sentence incorporates the ideas presented in the three original sentences, it is incorrect because the combination suggests an incorrect relationship between the ideas. By beginning with “Io,” the sentence places emphasis on the moon and the detail about the number of active volcanoes rather than the key idea that “scientists now believe that Jupiter may have as many as seventy-nine moons.” Since Io is an example of one of Jupiter’s moons, the details about Io should follow and be subordinate to the main clause, which provides new information about the number of Jupiter’s moons in general.
B. Incorrect. Although the sentence incorporates all three ideas from the original sentences and correctly places the detail about the number of active volcanoes on Io in a dependent clause, this option is incorrect because it presents an imprecise relationship between the ideas. By using the conjunction (connecting word) “and,” the sentence construction suggests that scientists “now believe” that “Jupiter may have as many as seventy-nine moons” and that “one of them is named Io,” instead of presenting Io as an example of one of Jupiter’s moons.
C. CORRECT. This sentence is the best way to combine the original sentences because it uses a complex sentence to present ideas clearly and precisely, and it shows the relationship between the ideas in the original sentences. The sentence starts by stating the number of moons scientists now believe Jupiter may have and then specifies that one of those moons is named Io. The dependent clause “which has the greatest number of active volcanoes in the solar system” immediately follows the word “Io” to provide additional information about the moon. A dependent clause contains a subject (“which,” referring to Io) and a verb (“has”) but is not a complete sentence on its own.
D. Incorrect. The sentence incorporates the key ideas from the original sentences, but its structure does not accurately present the relationship between these ideas. The beginning of the sentence includes the detail about Io having “the greatest number of active volcanoes in the solar system” before specifying that Io is one of the seventy-nine moons of Jupiter. The presentation of the details about Io at the beginning lessens the emphasis of the key idea that “scientists now believe that Jupiter may have as many as seventy-nine moons.”
Question analysis
This sentence-combining question gives three short sentences: scientists believe Jupiter may have as many as seventy-nine moons, one moon is named Io, and Io has the most active volcanoes in the solar system. Students must choose the single sentence that joins all three facts while showing how they relate, and the four versions differ only in order and connecting structure.
- Grade level
- Grade 7 reading and task
- Compared with grade 7
- At grade 7 Combining sentences so the ideas relate clearly is grade 7 language work. The three sentences are short, but every version keeps all the facts, so the choice rests on which idea leads and which is tucked into a clause, a typical grade 7 demand.
- 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
- A very close wrong answer moderate
- How sentences fit together moderate
- Every choice must be checked minor
- Evidence
- Answered from one sentence or line
- Reading level
- Question and choices: about grade 10, 162 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
Because every version keeps all three facts and is grammatical, the question is about emphasis and connection, which students rarely check for. Two versions open with Io and its volcanoes and leave the seventy-nine moons trailing after “and,” and one of them also calls Io a moon twice. The strongest pull is the version with the right order that still joins Io with “and,” so Io’s name reads as a second piece of news rather than an example of the moons just counted.
A very close wrong answer moderate Choosing the answer
The “and one of them is named Io” version matches the key in its order and in its which-clause about volcanoes; only its connector differs from the key’s “including one named Io.” (Embretson & Wetzel, 1987; Gorin & Embretson, 2006; Ascalon et al., 2007)
How sentences fit together moderate Working it out
Students must see that sentence 1 is the main news and that sentences 2 and 3 narrow to one example, so Io belongs inside the sentence about Jupiter’s seventy-nine moons. (Halliday & Hasan, 1976)
Every choice must be checked minor Choosing the answer
Every version is grammatical and keeps all three facts, so none can be ruled out by an error; each is judged on which idea leads and how the others attach. (Embretson & Wetzel, 1987)
Strategy: Decide which of the three sentences states the main idea and which ones add detail, then check whether each version’s order and structure show that relationship.
Traps
- Wrong transition: A connecting word or phrase that signals the wrong relationship, such as contrast where the idea continues.
- Changes the meaning: A revision is correct English but no longer says what the writer meant.
The wrong answers, classified
A Changes the meaning (Connors & Lunsford, 1988)
Opens with Io and its volcanoes and adds the moon count with “and,” so the main news about Jupiter trails behind its own example as an afterthought.
B Wrong transition (Halliday & Hasan, 1976)
Keeps the right order and the which-clause, but “and one of them is named Io” adds Io as a second piece of news instead of an example of those moons.
D Changes the meaning (Connors & Lunsford, 1988)
Leads with Io’s volcanoes, then says Io “is one of Jupiter’s moons” right after calling it “a moon,” and leaves the main news about Jupiter for the end.
Working it out, step by step
Figure out what the question asks
This asks for the best way to join three sentences into one. All four choices keep every fact. So the best one shows how the facts relate. Decide which fact is the main idea and which ones add detail.
Find the main idea
Sentence 1 is the big news: “Scientists now believe that Jupiter may have as many as seventy-nine moons.” Sentences 2 and 3 zoom in on one of those moons, Io. Io is an example of the moons, and its volcanoes are a detail about Io. So the main idea should come first, and Io should fit inside it.
Name the rule
Put the main idea in the main part of the sentence. Tuck the details in with words like including and which. For example: My school has thirty clubs. One is chess. The chess club meets on Fridays. Joined: My school has thirty clubs, including a chess club, which meets on Fridays.
Check each choice
- A is wrong. It starts with Io and its volcanoes. The main news about Jupiter trails at the end after “and.”
- B is wrong. The order is right. But “and one of them is named Io” adds Io as a second piece of news, not as an example.
- C is right. “Including one named Io” shows Io is one of the moons. Then “which” adds the fact about its volcanoes.
- D is wrong. It calls Io “a moon,” then says again that it “is one of Jupiter’s moons.” The main news comes last.
Watch out: B is very close to C. The only change is “and one of them is named Io” in place of “including one named Io.” The word “including” shows that Io belongs to the group.
Choose the answer
C leads with the main news and tucks in Io as an example. So the answer is C, “Scientists now believe that Jupiter may have as many as seventy-nine moons, including one named Io, which has the greatest number of active volcanoes in the solar system.”
Why this answer and not the closest wrong one
B is the closest wrong answer. It has the right order and the same “which” clause. But “and” tacks Io’s name on as a separate fact, as if it were more news. “Including” shows that Io is one of the seventy-nine moons. That ties the three facts together most clearly.
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The original DOE question
