A verb agreement question tests whether a verb matches its subject as one thing or more than one. Sort the forms by whether they work with it or they. Then find the true subject by asking who or what the verb is about, setting aside extra words between dashes. One thing takes a singular verb; more than one takes a plural verb. Words introduced by not don't add another subject.
Hints
- Hint 1
Look at who or what gets credit for the project's success. That's the subject the verb in the blank must match.
- Hint 2
Set aside the words between the dashes, then ask which word in “the engineers' resilience” names what gets the credit. Replace that subject with it or they to check the verb's number.
Step-by-step
Find the true subject
Step 1Sort the verb forms
Test the verb forms after it and they to sort them by number, meaning one thing or more than one. Although the forms also differ in tense, number is the first check. Which forms work with they? The forms were, have been, and are do, so they're plural. To find the subject they would have to match, ask what is credited with the project's ultimate success.
- Step 2
Find what gets the credit
The phrase between the dashes separates what gets credit from the verb. Does not add the formidable machinery to the subject the way and would? No: it rules the machinery out as the thing receiving credit, so set that phrase aside and look at the engineers' resilience. Within that phrase, engineers' tells us whose resilience it is, while resilience names what gets the credit. Even though several engineers share that quality, the verb matches what gets credit, not the people who have it.
- Step 3
Match the singular subject
Can we replace the engineers' resilience with it or they? Resilience names the ability to keep going through difficulty, so we're talking about one quality even if several people share it. The short check is it was credited, which makes was the singular form the subject needs. Choice D.