牛津高阶字典有说明: When you use "none of" with a plural noun or pronoun, or a singular noun referring to a group of people or things, you can use either a singular or a plural verb. The singular form is used in a formal style in British English: None of the trains is/are going to London. None of her family has/have been to college. Collins COBUILD English Usage 同样说,用单三是比较 ”formal“ 的。