音標發(fā)音英式音標 [?; e?]美式音標 [?; e]英式發(fā)音 美式發(fā)音 基本解釋art.一(個)；每一(個)；任一(個)n.英語字母表的第一個字母；學業(yè)成績得優(yōu)者；表示“最好”的符號同根派生 a相關(guān)詞用法辨析通常來說，a 是用在以輔音開首的詞前面，an 是用在以元音開首的詞前面； 可數(shù)名詞前面用 a（或 an），不可數(shù)名詞前面不可用a（或 an)，如可以說 a healthy boy，卻不可以說 a health； 在特定情況下，a（或 an）可以用在復(fù)數(shù)形式前面:習語中有a few (books)，a great many (books)等表示方法。在表示時間或款項的短語前面，如 a further five minutes。在若干在形式上是復(fù)數(shù)而在意思上是單數(shù)的單詞前面，如 a barracks，a links。在美國口語中，如 a good ways，a long ways； a（或 an）有時有“一個而不是那所要的一個”的意思。a 也有“任何一個”的意思。I got a letter indeed，but it was from a friend. 事實上，我收到了一封信，但只是一個朋友的來信。I wanted to read a book，I did not care whether it was a history，a novel，or a biography.a 與 few 搭配使用時，few 是“很少”，有“幾乎沒有”的意思。a few 是“若干”，有“頗有幾個”的意思。注意，only a few 卻等于 few，也是“很少”的意思。 a使用方法a詳細辨析英漢例句Liver and kidney are particularly rich in vitamin A.肝臟和腎臟富含維生素A。Details are available from the Hon. Sec. A.R. Bushby.詳情可咨詢名譽秘書A.R.布什比。I was assigned to Troop A of the 10th Cavalry.我被派往第10騎兵隊的A連。He brought me a large package.他給我送來一個大包裹.He missed the first prize by a whisker.他和頭獎擦肩而過.a更多例句詞組短語短語a cappella 無伴奏合唱;阿卡貝拉;走在大街的女子;無伴奏A little 一點;一些;一點兒;一點點Bisphenol A 雙酚A;雙酚;酚甲烷;丙二酚人馬座A Sagittarius ;Centaurus;sgrFORM A 普惠制產(chǎn)地證;普惠制原產(chǎn)地證明書;普惠證;普惠制原產(chǎn)地證a更多詞組英英字典劍橋英英字典(NOT PARTICULAR) used before a noun to refer to a single thing or person that has not been mentioned before, especially when you are not referring to a particular thing or person(ONE) one柯林斯英英字典 You use a or an when you are referring to someone or something for the first time or when people may not know which particular person or thing you are talking about. You use a or an when you are referring to any person or thing of a particular type and do not want to be specific. You use a or an in front of an uncount noun when that noun follows an adjective, or when the noun is followed by words that describe it more fully. You use a or an in front of a mass noun when you want to refer to a single type or make of something. You use a in quantifiers such as a lot, a little, and a bit. (a lot), (a little), (a bit##bit) You use a or an to refer to someone or something as a typical member of a group, class, or type. You use a or an in front of the names of days, months, or festivals when you are referring to one particular instance of that day, month, or festival. You use a or an when you are saying what someone is or what job they have. You use a or an instead of the number "one," especially with words of measurement such as "hundred," "hour," and "metre," and with fractions such as "half," "quarter," and "third." (one) You use a or an in expressions such as eight hours a day to express a rate or ratio. &rarran informal or dialect word for have &rarr(usually linked to the preceding noun) an informal form of of acceleration a劍橋字典a柯林斯字典專業(yè)釋義經(jīng)濟學1a 級(城市或公司債券的等級，低于 2a 級，高于 3b 級)生物學a 型血腺嘌呤(adenine)的符號；丙氨酸(alanine)的符號腺苷 (adenosine)極光激酶A (aurora)能源科學技術(shù)通風巷道,風道物理學(原子)質(zhì)量數(shù)(= mass number)埃(angstrom),埃單位(angstrom unit)的符號;亥姆霍茲函數(shù)(helmholtz function)的符號電子、通信與自動控制技術(shù)安 (ampere;amp)計算機科學技術(shù)安培 (ampere;amp)A磁碟機化學丙胺酸 (alanine;ala)丙氨酸 (alanine;ala)地球科學鉀霞橄黃長巖