假如你是李华，你的国际学校朋友paul邀请你下个星期天去他们学校参加文化交流活动并介绍中国传统绘画，但是你的爷爷生病住院，不得不谢绝他的邀请。请给paul一封回信。要包含以下内容：1.谢绝paul的邀请，2.说明你的理由，3.推荐你的同学Anna参加。词数为100词左右的英语作文！！！
Dear paul,
Thanks for inventing me to attend the Cultural exchange activities at next weekends to introduce Chinese Traditional Painting.I would really like to,but my grandpa was sick and I have to take good care of them at weekends.I am very sorry about it.I think Anna can take the place of mine to introduce the Chinese Traditional Painting.I will give her your email address and you can tell her something important and interesting about the activity.I wish you have a nice day.
yours,
Lihua.