If you are after a bike that you can ride to the subway and then take on the train with you, then you’ll want to pop into one of the many Dahon stores around town and pick up a folding bike.
I m after a dahon fold up bike of reasonable spec and light, not sure if 20" wheels is small enough folding? probably 7 gears, do you have second and as well as new? price between 1000 -2000RMB