Is the correct to say
A pack of wolves run through the woods
or is the correct English
A pack of wolves runs through the woods
The former sounds right. However, I think the subject is a pack and of wolves adds a description to the subject. In this case the subject is singular, so therefore the verb must be singular.
Am I correct? It just doesn't feel right.
This is a matter of formal agreement versus notional agreement.
Formal agreement is the strictly grammatical agreement between the verb and the subject: a singular subject must be matched by a singular verb.
Notional agreement is more flexible, and allows the verb to matched to the idea - notion- of the subject. For example
"The board of directors is in agreement"
versus
"The board of directors are arguing"
In the first, the notion is unity so a singular verb is appropriate, in the second the notion is disunity so a plural verb is used.
This works when the individuals and the collective are the same thing. 'The Board' and 'the directors' have the same referent. They are the same idea- the same thing. In your example 'the pack' and 'the wolves' are the same thing. This contrasts with, say, 'the bag of footballs' in which the 'the bag' and 'the footballs' are entirely different things.
As a native BE speaker, I would say that notional agreement is more usual in BE. Sometimes we treat groups as singular and sometimes as plural. Text books often say that formal agreement is more usual in AE, but I am not entirely convinced.
Getting around to your wolf pack, I would say:
"A pack of wolves runs through the woods."
because they run in unison. If they stopped to eat I would change:
"A pack of wolves eat [or "are eating"] in the woods"
because eating is an individual activity.
If somebody else said "A pack of wolves run through the woods" I wouldn't say it was wrong. It is just different.
Is only one sentence correct? Are both sentences acceptable?
It depends. It depends on the idea, concept or image you want to express.
A pack of wolves run through the woods
The verb, run, agrees with the plural noun, wolves. In other words, all the wolves (none excluded), run through the woods. The implication being that there are many wolves in this group.
A pack of wolves runs through the woods.
The verb, runs, agrees with the singular noun, pack. In this case, we look at the group of wolves as being a single unit. The pack is composed of individual wolves but because they each share common characteristics, we see them acting as a whole. As if they were an army of soldiers, which brings me neatly to:
"an army of soldiers is" has 421 results in Google books.
An army of soldiers is a powerfully organized, ferocious and destructive animal The Spirit of the Age, Volumes 1-2 By William Henry Channing
Whereas "army of soldiers are" has 1,800 results
An army of soldiers are turned loose in the blood stream that can kill anything that attacks it from cancer to the common cold A Cure to Die For by Stephen G. Mitchell
In the first example we see the soldiers as a single entity, powerful and unified. In the second we see each individual soldier as a potential threat to our health and well being.
It's this way! Take a look:
BLOODCURDLING CRIES SHATTER THE STILLNESS OF dusk in the Pantanal, in southern Brazil, as if a pack of wolves were gathering for a hunt._
No, it's this way! You take a look:
Some nights there is a pack of wolves that wakes him up with their howling...
Sorry to rain on your parade, but it's both ways. Watch and learn:
Some nights there is a pack of wolves that wakes him up with their howling
.
Both are correct, depending on whether you want to highlight the members of the group or the group itself. Please also read my short post about collective nouns on English Language Learners Stack Exchange.
(The examples are from the Corpus of Contemporary American English.)
EDIT - I'VE CHANGED MY MIND:
Ok, I concede defeat. We are dealing with collective nouns (something that should have been mentioned earlier), and it is true that the normal rules of grammar do not always apply here. There are certainly grammar sources that will argue that there are rules concerning where you should/shouldn't use singular/plural verbs with collective nouns. Eg: http://www.grammar-monster.com/lessons/singular_plural_%20collective_noun.htm and http://www.chompchomp.com/terms/collectivenoun.htm But these rules are so convoluted and unrealistic, that they appears to be an attempt to impose logic post facto to a situation that will not allow a single, simple, solution.
A better source is: http://oxforddictionaries.com/us/words/matching-verbs-to-collective-nouns-american and it pretty much says what was said in the original comments, so consider me to have withdrawn from this argument in shame-faced defeat ;-)
The best advice of all is probably: 'if in doubt, reword the sentence in a way that avoids the problem'.
ORIGINAL POST:
I disagree with @choster and @Peter Shor, the gramatically correct sentence in both American and British English is
A pack of wolves runs through the woods
As you correctly surmise, 'pack' is the singular subject, and the fact that it contains a plurality of wolves is not relevant to the sentence.
While in 'real life' you'll hear the other version quite often in informal spoken English (relating to things that are alive), it is not correct grammar any more than it would be to say.
The bag of footballs overflow
or
The many-windowed building are beautiful
