求翻译：我下个星期六上午不得不去看牙医，下午又要去看外婆，晚上还要写很多的作业，所以，对不起，不能参加你的生日聚会啦，真的很抱歉。谢谢你对我的邀请。是什么意思？

I had to go to the dentist next Saturday morning, afternoon and also to see the grandmother, but also write a lot of work at night, so I'm sorry, can not attend your birthday party friends, really sorry. Thank you for my invitation.

I had to go to a dentist next week, 6 am to 1 pm, 9 pm to see my grandmother would also like to write a lot of operations, therefore, I am sorry, you cannot participate in the birthday party, if there really are sorry. Thank you for inviting me.

Under me Saturday morning can not but go to see the dentist, must go in the afternoon to see the grandmother, evening also must write very many works, therefore, sorry, cannot attend your birthday meeting, really very much was sorry.Thanks you to my invitation.

I next Saturday morning had to dentist, again this afternoon visit grandma at night writing lots of homework so sorry, cannot attend your birthday party really sorry. Thank you for invitation.

Under me Saturday morning can not but go to see the dentist, must go in the afternoon to see the grandmother, evening also must write very many works, therefore, sorry, cannot attend your birthday meeting, really very much was sorry.Thanks you to my invitation.