I was wondering if you were doing anything this weekend

I was wondering if you were doing anything this weekend
对于这个橘子有点疑问,为什么从句用were 课这个if是是否,不是如果嘛?为什么要虚拟呢?因为语气的关系?
而且为什么不说i am wondering.
和i wonder有有何不同
时态一致也该would be free吧