英语作文，帮我看看这是作文中的一段话，帮我稍微改改，有什么语法问题请指出，作文是关于邀请信的，多谢

如果主要是说明举办聚会的原因，就这么改好了
One reason why we are holding the party is to celebrate the birthday of our tutor, who will also be invited to it; another is that we'd like to get together before graduation when we part from each other.
还有别的信息要写进去吗

We will gather together and hold one party before graduation to celebrate our tutor's birthday.
目的就是庆祝导师的生日和毕业前的聚会，表示清楚就行，重要的是简单明了。
希望能采纳。

For one thing,that day is the birthday of our tutor,then we will a party and also invite him together with us before the graduation and leaving.