A verb form question tests whether the blank needs a main verb, which says what its subject does or is. Find the blank's own subject, then sort the forms. Read past extra words to the period, skipping other subjects' verbs. Count that subject's main verbs: none means the blank adds one; one means it only describes, unless it joins a list of verbs. Use -ing when the noun does something and -ed when something is done to it.
Hints
- Hint 1
The blank sits inside the part introduced by that. Find the subject of that part, rather than counting every verb in the whole sentence.
- Hint 2
Read beyond the second comma and look for the verb that tells what the project does.
- Hint 3
Ask who holds what back in the words beginning with by. Is the project doing something, or is something being done to the project?
Step-by-step
Count verbs, then check who does what
Step 1Find the blank's subject
Although the early correspondence begins a separate part with the verb reveals, and surviving drafts of Lovelace's notes make clear has make as its verb. Which subject, the thing we're talking about, belongs to the blank? The word that begins a clause, a group of words with a subject and verb, about the project. So count the project's verbs, not those of the correspondence or drafts.
- Step 2
Read past the blank
Read past the phrase between the commas to advanced more slowly than either had expected. Does the project already have a main verb, the verb that says what it does or is? Yes: advanced tells what the project did, while had expected tells what Lovelace and Babbage expected. The blank only describes the project, because there's no new clause or joined list of verbs there. The forms had hindered and hinders would add another main verb without a word to join it to advanced.
- Step 3
Check what happens to the project
Who does the holding back in by frequent design revisions and inadequate funding? Those problems hold the project back, so the project has something done to it. An -ing form describes a noun doing something, which means hindering would make the project do the holding back. To test the -ed form hindered, add was: the project was hindered says what the text means, so hindered without was describes what happened to the project instead of adding another main verb. Choice C.