关于IllusionTime is an illusionTime is illusion 是不是都可以?百度了下能搜索到带的Illusion的句子前面都有不定冠词an,这个an是不是必须要添加的?为什么?

关于IllusionTime is an illusionTime is illusion 是不是都可以?百度了下能搜索到带的Illusion的句子前面都有不定冠词an,这个an是不是必须要添加的?为什么? 关于No man is an Island的英文演讲 关于an invitation to有一句句子是不是“Carelessness is an invitation to the accident.意思是“粗心导致事故” a an 名词单复数变化 ,出十小题,就是关于a an 的用法,不可数名词和可数名词,例：this is an arm.急用急用 . AN OWL IS AN OWL IS AN OWL怎么样 句型转换,关于That is such an .That is such an important meeting that we should attend it.改为It is____ ______a meeting that we should attend it 关于it is 开头的句子,作文开头,想写it is an increasingly argument that .这个句式OK吗?有an还是没有? Mike is an English She is an American. Tom is an E________boy. No man is an It is an eraser. Is this an egg? Is she an apple? She is an American. It is an eraser? this is an easy this is an