Question 130·Easy·Form, Structure, and Sense
Known for its dazzling rings, Saturn, along with its many moons, ____ a frequent target of space telescopes.
Which choice completes the text so that it conforms to the conventions of Standard English?
For subject-verb agreement questions, first cross out any interrupting phrases set off by commas (such as "along with its many moons"), prepositional phrases (like "of space telescopes"), and other modifiers. Match the verb directly to the core subject you’re left with, checking if it is singular or plural. Then choose the tense that fits the context—general facts usually take simple present—so you can quickly eliminate answer choices with the wrong number or tense.
Hints
Locate the true subject
Temporarily ignore the phrase "along with its many moons." Read the sentence without that middle part and see what the subject and verb should be.
Check singular vs. plural
Ask yourself: Is the subject naming one thing or more than one thing? The verb must match that number.
Think about the time of the action
Is the sentence talking about something that was true only in the past, or a general fact that is true now and usually true over time? Choose a tense that fits that idea.
Step-by-step Explanation
Identify the core subject
First, strip away the extra information to find the true subject. The sentence is:
"Known for its dazzling rings, Saturn, along with its many moons, ____ a frequent target of space telescopes."
If you remove the phrase "along with its many moons," the core clause is:
"Saturn ____ a frequent target of space telescopes."
So the subject is "Saturn."
Determine if the subject is singular or plural
"Saturn" is the name of one planet, so it is singular.
The phrase "along with its many moons" is an interrupting phrase that adds extra information. It does not change the subject from singular to plural. The verb must still agree with the singular subject "Saturn."
Choose the correct tense for the sentence
The sentence describes a general, ongoing fact about Saturn and space telescopes. General facts are normally stated in the simple present tense (for example, "The Earth orbits the sun," "Water boils at 100 degrees Celsius").
So we want a singular verb in present tense to match "Saturn" and the meaning of the sentence.
Select the answer that fits subject and tense
Now check each option:
- "are" = present tense, plural verb → does not match singular "Saturn"
- "have been" = present perfect tense, suggests ongoing/past action, and is used with plural subjects or "you/they" → wrong number and tense
- "were" = past tense, plural verb → wrong time and number for a general fact
- "is" = present tense, singular verb → correctly matches the singular subject and the general-fact meaning
Therefore, the correct answer is "is."