This problem is complicated and controversial in practice as well as in theory.

这不仅是实践上一个十分复杂的问题，而且在理论上也是颇多争议。

youdao

This problem is complicated and controversial in practice as well as in theory.

这不仅是实践上一个十分复杂的问题，而且在理论上也是颇多争议。

youdao