a是什么意思,a怎么读


a基本信息

读法:英 [ə; eɪ] 美 [e]

释义:

  • n. 字母A;第一流的;学业成绩达最高标准的评价符号
  • abbr. [物]安(ampere)
  • 使用频率:★★★★★

    星级词汇:★★★★★

    英英释义

    Noun:

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

    a 一 (个)

    不定冠词an在发展过程中出现的缩略形式,应用于首字母为辅音的单词及h发音单词。

    a
    a: [OE] The indefinite article in English is ultimately identical with the word one (as is the case, even more obviously, in other European languages – French un, German ein, and so on). The ancestor of both a(n) and one was ān, with a long vowel, but in the Old English period it was chiefly used for the numeral; where we would use a(n), the Anglo-Saxons tended not to use an article at all. Ān begins to emerge as the indefinite article in the middle of the 12th century, and it was not long before, in that relatively unemphatic linguistic environment, its vowel became weakened and shortened, giving an.

    And at about the same time the distinction between an and a began to develop, although this was a slow process; until 1300 an was still often used before consonants, and right up to 1600 and beyond it was common before all words beginning with h, such as house.

    => one
    a (1)
    indefinite article, mid-12c., a variation of Old English an (see an) in which the -n- began to disappear before consonants, a process mostly complete by mid-14c. The -n- also was retained before words beginning with a sounded -h- until c. 1600; it still is retained by many writers before unaccented syllables in h- or (e)u-, but is now no longer normally spoken as such. The -n- also lingered (especially in southern England dialect) before -w- and -y- through 15c.
    a (2)
    as in twice a day, etc., from Old English an "on," in this case "on each." The sense was extended from time to measure, price, place, etc. The habit of tacking a onto a gerund (as in a-hunting we will go) died out 18c.

    词态变化

    权威造句

    1. Liver and kidney are particularly rich in vitamin A.
    肝脏和肾脏富含维生素A

    来自柯林斯例句WwW.wENTIYi.cOM

    2. Details are available from the Hon. Sec. A.R. Bushby.
    详情可咨询名誉秘书A.R.布什比。

    来自柯林斯例句

    3. I was assigned to Troop A of the 10th Cavalry.
    我被派往第10骑兵队的A连。

    来自柯林斯例句

    4. Passes are graded from "A" down to "E".
    及格分为A到E几等。

    来自柯林斯例句

    5. Use only clean, Grade A, perfect eggs.
    只用表面干净、无磕碰的A级鸡蛋。

    来自柯林斯例句

    近反义词

  • with a pinch of salt 有保留地
  • stand a chance 有希望
  • a dose of one"s own medicine 自己惹来的恶果,自己...
  • flog a dead horse 徒劳无益
  • keep a stiff upper lip 坚定不移(顽强不屈...
  • a bag of bones 骨瘦如柴的人...
  • once in a blue moon 罕见的,极少的,难得...
  • show a clean pair of heels 逃走(溜之大吉)...
  • birds of a feather 同类型的人
  • with a grain of salt 有保留地
  • bring to a stand 终止
  • turn over a new leaf 重新开始
  • as a matter of fact 事实上
  • bring to a standstill 结束(使终止...
  • turn up again like a bad penny 不要它偏又回来,挥去...
  • at a loose end 无事做
  • throw a fit 大发脾气
  • blow a fuse 使保险丝熔断(勃然大...
  • cut a poor figure 出丑
  • take something with a grain of salt 将信将疑
  • 相似短语

  • such a 这样的…
  • with a will 热情地,起劲地
  • not a 一个也不
  • a bit of a 有点…的味道
  • a hack of a lot of 好多好多…
  • a slip of a girl n. 瘦长的姑娘
  • a storm in a teacup n.<主英>茶杯里掀起的大风暴,小事引起的轩然大波,小题大作,大惊小怪
  • a tempest in a barrel n. 小题大作
  • a year and a day 满一年,整一年
  • a canidate for a vacancy 候补
  • 单词分析

    暂无,等待补充.

    记忆方法

    暂无,等待补充.

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