I am a PhD student in Physics in Bonn, Germany.
Zhong Yuan and his girlfriend are both great guests. They are friendly and considerate. Also, the room barely looked like anyone had stayed! We'd be happy to host them again.
Zhong Yuan Lai is a really nice guy. Very discrete and respectful, he took care of my studio for 2 weeks without any problem. He is very serious and was working during all that time. The communication was very good and I knew since a long time the arrival and departure date. Lai speeks very good english, that's useful ! We have had a friendly relationship : your welcome again Lai !