I raised this question as I was interested in which to choose between plural verbs or singular verbs for collective nouns, and I happened to find a good material in the following. The logic goes like "If each member of a collective noun does the same thing, you should use singular verbs and pronouns, while if each does different things, plural verb and pronouns." and this makes sense. But judging from what you said, it may not be true again like other grammar theories. I always find the reality of English here different from what I learned in grammar books and materials. I wonder if I have to follow the rules here.
**I'm sorry I couldn't find the material website link, so I just post the MS-word version I've saved.
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People often behave in the same manner, doing one thing in unison with the other members of their group. When these people are part of a collective noun, that noun becomes singular and requires singular verbs and pronouns. As you read the following examples, notice that all members of the collective noun are doing the same thing at the same time:
1.Every afternoon the baseball team follows its coach out to the hot field for practice.
Team = singular; follows = a singular verb; its = a singular pronoun. All members of the team arrive at the same place at the same time.
2.Today, Dr. Ribley's class takes its first 100-item exam.
Class = singular; takes = a singular verb; its = a singular pronoun. All members of the class are testing at the same time.
3.The jury agrees that the state prosecutors did not provide enough evidence, so its verdict is not guilty.
Jury = singular; agrees = a singular verb; its = a singular pronoun. All members of the jury are thinking the same way.
Members of collective nouns can behave in a similar fashion. When the members are acting as individuals, the collective noun is plural and requires plural verbs and pronouns. As you read these examples, notice that the members of the collective noun are not acting in unison
1. After the three-hour practice under the brutal sun, the team shower, change into their street clothes, and head to their air-conditioned homes.
Team = plural; shower, change, head = plural verbs; their = a plural pronoun. The teammates are dressing into their individual outfits and leaving in different directions for their individual homes.
2.After the long exam, the class start their research papers on famous mathematicians.
Class = plural; start = a plural verb; their = a plural pronoun. The students are beginning their own research papers—in different places, at different times, on different mathematicians.
3.The jury disagree about the guilt of the accused and have told the judge that they are hopelessly deadlocked.
Jury = plural; disagree, have told = plural verbs; they = a plural pronoun. Not everyone on the jury is thinking the same way.
Whenever you cannot decide if a collective noun is singular or plural, exercise your options as a writer. You have two ways that you can compose the sentence without causing an agreement error: 1) insert the word members after the collective noun [jury members, committee members, board members], or 2) use an entirely different word [players instead of team, students instead of class, soldiers instead of army]. Then you can use plural verbs and pronouns without worrying about making mistakes or sounding unnatural.
