There is only a singular form, but it has a plural meaning. When it is used as the subject, the predicate is plural. Not used with (n), but can be used with. People will laugh at you. People will laugh at you. The police are looking for him. The police are looking for him. Many cows were killed for it. Many livestock were slaughtered as a result. Note: The unit prefix is used to indicate the number of heads of livestock. Such as: five cows, five cows, fifty cows, fifty cows.
Collective noun is plural in form and plural in meaning. This category includes goods, clothes, etc. Its usage is characterized by its only plural form (of course, it also means plural, and the predicate is plural when it is used as the subject), but it is usually not used with numerals.
Clothes dry slowly in rainy season. Clothes don't dry easily in rainy season. Such clothes are very expensive. Clothes like that are very expensive. If the product is of poor quality, you should complain to the manufacturer. If the goods are of poor quality, you should complain to the manufacturer.
Extended data can be divided into collective noun: such things can be individualized, can be counted by set quantifiers, and can also be counted by individual quantifiers other than "one".
For example, police, originally referred to as cadres and policemen in public security departments, can say that "a group of policemen are still on duty at the front line in the cold midnight" or "five policemen are commended", but it cannot be said that "as an ordinary judicial policeman, I can also work for ordinary people".
Collective noun: This thing cannot be individualized, that is, it is not modified by individual quantifiers. Besides being modified by set quantifiers, it can sometimes be modified by container quantifiers, quantifiers or indefinite quantifiers.
Baidu Encyclopedia-collective noun