I think it very well that I play basketball.
这个句子的结构混乱,而且用词不妥.
改法一：I think it very good for me to play basketball.
think it +形容词+to do,认为做某事如何,it为形式宾语,to do为实际上的宾语.
改法二：I think (that) it's very good for me to play basketball.
I think后是that引导的宾语从句,that可省略.