久青草国产手机视频免费观看_毛片网站是多少_亚洲视频中文_一区二区高清在线

首頁英語詞典precursorprecursor英英釋意

precursor

英 [pr?'k??s?] 美[pri'k?s?]
  • n. 先驅(qū),前導(dǎo)

英英釋意


1. a substance from which another substance is formed (especially by a metabolic reaction)
2. a person who goes before or announces the coming of another
3. an indication of the approach of something or someone