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