The rule says that a plural subject must have a plural verb form.根据规则，主语是复数时，动词也要用复数形式。If the subject is plural, the verb has to be in the plural number.如果主语是复数，动词必须是复数形式。He was referring to himself in the plural.他在用复数形式指称自己。The word is usually used in the plural.这个词通常用复数形式。