Determiner asking for a choice among known options before a noun

• Used to specify one or some from a set

疑问限定词，用于名词前，在已知选项中作选择

• 指定从一组中哪一个或哪些

Pronoun asking which one or ones among known options

• Stands alone without a following noun

疑问代词，询问在已知选项中哪一个或哪些

• 不带后续名词单独使用

Relative pronoun introducing a nonrestrictive clause about a prior noun

• Can refer to a whole previous statement or situation

关系代词，引出非限制性从句，补充说明前文内容

• 也可指代整个前述陈述或情况

Relative pronoun or determiner introducing a restrictive clause modifying a noun

• Often interchangeable with that in modern use

关系代词或限定用法，引出限制性定语从句修饰名词

• 现代用法中常与 that 互换