Question 226·Easy·Form, Structure, and Sense
A team of engineers determined that the prototype drone, along with its spare batteries, ______ able to operate for more than two hours without recharging.
Which choice completes the text so that it conforms to the conventions of Standard English?
For Standard English subject-verb agreement questions, first strip away interrupting phrases and prepositional phrases to reveal the core subject (e.g., remove "along with...," "together with...," "in addition to..."). Decide if that subject is singular or plural, then match it with a verb that also fits the sentence’s time frame (past, present, etc.). Eliminate any options that mismatch in number or tense, and read the sentence back in full to confirm it sounds grammatically consistent.
Hints
Find the real subject
Cover up the phrase between the commas ("along with its spare batteries") and see what the subject of the clause before the blank really is.
Decide singular or plural
Once you know the subject, ask: is it one thing (singular) or more than one thing (plural)? The verb must agree with that.
Match the time of the action
Look at the verb "determined" earlier in the sentence. Is it describing the present or the past? Choose a verb form in the blank that fits that same time frame while still agreeing with the subject.
Step-by-step Explanation
Locate the subject and the verb spot
First, find what is doing the action or being described. The sentence says:
"A team of engineers determined that the prototype drone, along with its spare batteries, ______ able to operate..."
The blank is part of the clause "the prototype drone, along with its spare batteries, ______ able to operate." That means the missing word is a form of the verb "to be" that links the subject to "able to operate."
Ignore interrupting phrases to find the true subject
The phrase "along with its spare batteries" is extra information. It does not turn the subject into a plural; it just adds a detail.
If you temporarily remove that phrase, the core of the clause is:
"the prototype drone ______ able to operate for more than two hours..."
So the true subject is "the prototype drone", which is singular.
Match the verb to the singular subject and past time
Now consider two things:
- Number (singular/plural):
- A singular subject ("drone") needs a singular verb.
- Tense (time):
- The main verb "determined" is in the past tense, so the verb in the "that" clause should also describe a past situation, not present.
Look at the options and ask: which choice is both singular and describes a simple past situation?
Choose the singular past-tense verb
Check each option:
- "are" – present tense plural
- "were" – past tense plural
- "have been" – present perfect, usually plural or with "I"
- "was" – past tense singular
Only "was" is singular and clearly matches the past-time context set by "determined." The completed sentence is:
"A team of engineers determined that the prototype drone, along with its spare batteries, was able to operate for more than two hours without recharging."