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    1. 首頁英語詞典aa英英釋意

      a

      英 [?; e?] 美[e]
      • n. 字母A;第一流的;學業(yè)成績達最高標準的評價符號
      • abbr. [物]安(ampere)

      英英釋意


      1. the blood group whose red cells carry the A antigen
      2. a metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation
      3. any of several fat-soluble vitamins essential for normal vision; prevents night blindness or inflammation or dryness of the eyes
      4. one of the four nucleotides used in building DNA; all four nucleotides have a common phosphate group and a sugar (ribose)
      5. (biochemistry) purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
      6. the basic unit of electric current adopted under the Systeme International d'Unites;
      "a typical household circuit carries 15 to 50 amps"
      7. the 1st letter of the Roman alphabet