"I`m a keyboard operaror"和"I`m an engineer"为何要加上"a"和"an",是为我区别男女吗?

I'm a keyboard operator.汉语怎莫说? 英语改错：I’m a keyboard operater I'm a keyboard operater.改错 i am a keyboard operator.i operate keyboard.这么说行吗?看新概念看到的keyboard operator I`m a keyboard operaror和I`m an engineer为何要加上a和an,是为我区别男女吗? keyboard .. keyboard an和a的用法?SOPHIE:I'm a keyboard operator和ROBERT:I'm an engineer两句话中有a和an两个词.我不清楚为什么分别用这两个词?都用同一个词不行吗? A question about keyboard operatorWhere is colon on the keyboard dose a computer have a keyboard? It’s a keyboard.写问句. She is a keyboard operator变为复数 The boy used a keyboard to ----- the window of his new computer game.A.restartB.openC.controlD.print为什么选B？Tommy,may I use your computer?--------------.It can not be started.为什么用I'm afraid not。I'm afraid not不是“恐怕不是” oper the front cover,then replace the toner cartridge with a new one 大哥大姐们. mechanical keyboard,membrane keyboard 怎么翻译oper income Oper ative 是什么意思 新概念 英音发音辨别求教?http://www.kekenet.com/nce/4880.shtml这是第一册第7课,其中倒数第三句,I'm a keyboard operator. 其中operator我怎么听都像是//,正确音标应该是,但是美音版则是很清楚的.你们听