You can understand the main ideas of complex texts dealing with both concrete and abstract topics, even if they are of a technical nature as long as they are within your field of expertise.

He is capable of relating to native speakers with a sufficient degree of fluency and naturalness so that communication is carried out without effort on the part of either interlocutor.

He can produce clear and detailed texts on various topics, as well as defend a point of view on general topics indicating the pros and cons of different options.