"empty category"的定义和意义

What is an "empty category"?

An empty category is a syntactic position in a sentence that does not have a visible word or phrase but is necessary for grammatical correctness. This concept is often used in generative grammar, where some elements may be implied rather than directly stated. Empty categories can include traces, showing where a moved element came from, or pro, which refers to an implied pronoun. Recognizing empty categories helps in understanding sentence structure and meaning, even when words are missing.