a
［误］ I think it is an useful English dictionary.
［正］ I think it is a useful English dictionary.
［析］ 在不定冠词a与an的 用法中要注意的一点是：an用在以元音开头的词之前；而a则用在以辅音开头的词之前。要特别注意的是以u字母打头的单词，如useful,university等，其第一个音标是［j］，所以要特别予以注意。
［误］ I need a hour to finish this letter.
［正］ I need an hour to finish this letter.
［析］ 要注意hour和honest的第一个字母不发音。
［误］ My teacher is a unknown man, but he is a very good man.
［正］ My teacher is an unknown man, but he is a very good man.
［析］ 要注意以u打头的单词，它的发音为［］时，单数名词前要用an，如uncle等。
