an alarm clock中的冠词为什么要用an?而不能用a?

an alarm clock中的冠词为什么要用an?而不能用a? The alarm clock is an a____ invention. an alarm clock 闹钟 alarm也不是形容词啊,怎么修饰clock? This is an alarm clock 为什么要用an? dresser,an,clock,the,there,is,on,alarm(.) There is —(a /an )alarm clock on the table . there is an alarm clock on the table.改为复数 把The girl has an alarm clock变为复数形式 alarm o'clock还是alarm clock? where’s an alarm clock和where’s the alarm clock这两句话谁对,或者说两句都对? an alarm an.alarm. an alarm alarm clock用英语翻译 Most peole wear or carry____ A.an alarm clock B.an alarm C.a clock D.a watch 新概念2里的Lesson 947页第11题 Do you have an alarm clock?和Does your mother have a sister?怎么答? 提问题sister,does,alarm,clock,have,Tina's,an.连词成句 用 clock ,not ,an ,does ,alarm ,have ,Sonia 组成一段话