there is an exercise book in the desk(划线部分提问,划线的是an)快,急!星期天之前

问题描述:

there is an exercise book in the desk(划线部分提问,划线的是an)
快,急!星期天之前

Hao many exercise book in the desk.

exercise 是元音发音开头,单数用an 我没看懂你的提问意思,写详细点