He taught me how to study,which includs flowing steps.为什么不用including

因为which后面跟的是从句，从句除了which作为主语，其他的和完整的句子是一样的，所以动词不需要改变形式。
如果要用including的话要这么说：
He taught me how to study ,including flowing steps.
或者可以用included：
He taught me how to study, flowing steps included.