理论以实践为基础，又转过来为实践服务。

Theory is based on practice and in turn serves practice.

youdao

众所周知，理论以实践为基础，反过来，又为实践服务。

It is known that theory is based on practice and in turn serves practice.

youdao

众所周知，理论以实践为基础，反过来，又为实践服务。

It is known that theory is based on practice and in turn serves practice.

youdao