Theresa, I couldn't find this in the style guide (yet-- still looking :). Jeff asked me if this is singular or plural (Word grammarcheck insists it's singular):
The rest of the group (was/were) left behind.
My first thought was that it was singular (because "rest" is singular), but then I thought maybe plural. (Nothing if not decisive here. :) I said if "the rest" was actually substituting for a portion (like "Half the group"), it was singular, but if it was substituting for a number (like "Two members of the group"), it's plural if the number is more than 1. I realize that half of four is two, so the antecedents for "the rest" would amount to the same thing, so it's actually more of a matter of emphasis. Did he want to emphasize the individuality of the "left-behind" (two), or the decimation of the group (half left behind and the group bisected)?
Collective nouns represent both a single entity (the group) and more than one entity (the individual members together), so you often have to do some thinking about which you're referring to at the moment. It might help to think of the singular group as being in consensus or acting as one (The committee was pleased with your report and was planning to approve your request) or in disagreement (the audience were divided about the third act). (I might add that this is not something most readers are likely to take issue with either way, but your choice might emphasize the unity or disunity of the group subliminally.)
It might help to see if the meaning comes across if you add "members" to the collective noun (that is, plural-- emphasizing the individuals). The rest of the group members were left behind? But if adding "members" or some other individual marker messes with the meaning because you are really talking about a unified group, then you might go with the singular verb. (I just want to put in here that S/V agreement is really unnecessary in a language where "number" is already marked on the noun -- cat/cats-- but does anyone in charge listen to me and change the grammar? NOOOOOO.)
Now in Britain, collective nouns are mostly treated as plural-- The team are ready for the game Friday. In fact, along with adding U to "-or" words, this is one of the most visible differences between British and American English. So it's a good idea to consider the nationality of your publisher!
Here's an example of "when in doubt, take it out!"
The team sprang to its feet, eager to take the field.
Well, the team is acting as one, so singular, but... but... "its feet"? Sounds like the team is a centipede! How about recasting to get rid of feet altogether?
The team sprang up--?
The crew team rested its oars, content with third place?
What do you all think?