🔑aBrE/ə/NAmE/ə/BrEstrong form/eɪ/NAmEstrong form/eɪ/ (also anBrE/ən/NAmE/ən/BrEstrong form/æn/NAmEstrong form/æn/) indefinite articleHELP The form a is used before consonant sounds and the form an before vowel sounds. When saying abbreviations like 'FM' or 'UN', use a or an according to how the first letter is said. For example, F is a consonant, but begins with the sound /e/ and so you say: ◆an FM radioU is a vowel but begins with /j/ and so you say: ◆a UN declaration * a 用于辅音前,an 用于元音前。在 FM、UN 等缩略语前,用 a 还是用 an,需视首字母如何发音而定。如 F 是辅音字母,但其发音以 /e/ 开头,故应说:an FM radio。U 是元音字母,但其发音以 /j/ 开头,故应说:a UN declaration。🔑usedbeforecountableorsingularnounsreferringtopeopleorthingsthathavenotalreadybeenmentioned(用于可数名词或单数名词前,表示未曾提到的)一(人、事、物)◆aman/horse/unit一个人;一匹马;一个单位◆anaunt/egg/hour/X-ray一位姑母;一枚鸡蛋;一小时;一张 X 光片◆Icanonlycarrytwoatatime. 我一次只能带两个。◆There'savisitorforyou. 有位客人找你。◆She'safriendofmyfather's(= oneofmyfather'sfriends). 她是我父亲的朋友。🔑usedbeforeuncountablenounswhenthesehaveanadjectiveinfrontofthem, orphrasefollowingthem(用于前有形容词或后有短语的不可数名词前)◆agoodknowledgeofFrench精通法语◆asadnessthatwon'tgoaway挥之不去的悲愁🔑any; every任何一;每一◆Alionisadangerousanimal. 狮子是猛兽。🔑usedtoshowthatsb/sthisamemberofagrouporprofession(表示为某一群体或职业中的一员)◆Theirnewcar'saBMW. 他们的新轿车是辆宝马。◆She'saBuddhist. 她是佛教徒。◆He'sateacher. 他是教师。◆IsthataMonet(= apaintingbyMonet)? 那是莫奈的画吗?usedinfrontoftwonounsthatareseenasasingleunit(用于视为一体的两个名词之前)◆aknifeandfork一副刀叉usedinsteadofonebeforesomenumbers(用于某些数字前,代替 one)◆Athousandpeoplewerethere. 那里有一千人。usedwhentalkingaboutprices, quantitiesandrates(用于价格、数量、比率等)一,每一SYNper◆Theycost50pakilo. 这些东西一公斤 50 便士。◆Icantype50wordsaminute. 我每分钟能打 50 个单词。◆Hewasdrivingat50milesanhour. 当时他正以每小时 50 英里的速度驾车。apersonlikesb像(某人)的人;…式的人物◆She'salittleHitler. 她是个小希特勒。usedbeforesb'snametoshowthatthespeakerdoesnotknowtheperson(用于某人姓名前,表示说话者不认识此人)有个◆There'saMrsGreentoseeyou. 有位格林太太要见你。usedbeforethenamesofdaysoftheweektotalkaboutoneparticularday(用于一星期中某天的名称前,表示具体某一天)◆ShediedonaTuesday. 她是在某个星期二去世的。