I went to swimming.swimming不是swim的ing形式吗?它在这个句子中做什么成分,为什么不用s

I went to swimming.swimming不是swim的ing形式吗?它在这个句子中做什么成分,为什么不用swim呢?
I like playing football.like,playing不都是动词吗?句中能有两个动词吗?playing在这个句子中做什么成分,为什么不用play呢?
He often playing basketball.变一般疑问句：Do he often play basketball?
I hope you will get better soon.句中的will能用be going to代替吗?如果不能,为什么?
Tom is (reading books) in the classroom.括号里的能写成reading a book?
My sister was busy yesterday.=My sister ___a busy ____yesterday.(had day)对吗?yesterday不就是名词吗?为什么还加day?能写成My sister had busy yesterday吗?不能的话,为什么?