I have an idea.那如果在 idea 面前加个 great ,那 idea 面前该加 a 还是 an

I have an idea.那如果在 idea 面前加个 great ,那 idea 面前该加 a 还是 an idea 是不是加an I have an another idea 还是没有an I have some idea.的idea是加s还是不加s呢 是an good idea 还是 a good idea ,为什么 是an good idea还是a good idea? I have an idea 变否定句 have a knowledge of 和 have an idea of I'm not sure mens____________ A.I have an idea B.I don't now get an idea he got an idea Do you have an idea about________?