Mr Wong and two fellow activists are now facing jail for taking part in last year's protests.
Claudia Mo resigned from Hong Kong's Legislative Council after four colleagues were expelled.
By Preeti Jha
Pro-Beijing lawmaker Michael Tien says China needed to take action to allow Hong Kong's legislature to function.
Pro-democracy lawmaker Claudio Mo says they have lost all power to block pro-China legislation.
All of Hong Kong's pro-democracy lawmakers have resigned after Beijing dismissed four of their colleagues.
Other opposition lawmakers had threatened to resign if this happened
By Grace Tsoi
By Michael Bristow
Thai and Hong Kong pro-democracy youth activists have joined forces, even sharing protest tactics.