1 PREFIX （用于名词和形容词前）表示“二”，“两”，“双” Bi- is used at the beginning of nouns and adjectives that have 'two' as part of their meaning. （用于名词和形容词前）表示“二”，“两”，“双”

2 PREFIX （用于构成形容词和副词）表示“每…两次”，“两…一次” Bi- is used to form adjectives and adverbs indicating that something happens twice in a period of time or happens once in two periods of time that follow each other. （用于构成形容词和副词）表示“每…两次”，“两…一次”