楼上为什么说要用完成时?
这句是非真实条件状语从句的虚拟
从句谓语动词用一般过去式,即 If she were here
主句谓语动词形式should/would/could/might+动词原形（过去将来时）,即本句的I would invite her for supper
If she were here,I would invite her for supperat home.
还有invite sb.for sth.
invite sb.to do sth.