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noun
  1. (Mathematics)a significant zero in the decimal representation of a number
    (数)有效零
    ■a symbol or piece of text used in a mathematical expression or in an instruction in a computer program to denote a missing quantity or operator
    占位符号
  2. (Linguistics)an element of a sentence that is required by syntactic constraints but carries little or no semantic information, for example the word it as a subject in it is a pity that she left, where the true subject is that she left
    (语言学)占位成分(句法规则要求,但又没有语义信息的句子成分,例如: it is a pity that she left一句中的主语it,that she left才是真正的主语)
英语宝典
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