是病句.
有很多种改法啊,我给你说说吧.
We have three invitations; so we can come to the party.中间要用分号,因为前后两个都是完整的句子.
We three have been invited and we can come to the party.
还有改成疑问句什么的,太多了,我估计你就是想把它改成正确的吧,我就不一一跟你讲啦~