Look!So many colorful bicycles in two lines over there.
They're for public.This ______ of green smart traffic is everywhere in Xiangyang city.( )
A.numberB.pairC.kindD.piece
Look!So many colorful bicycles in two lines over there.
They're for public.This ______ of green smart traffic is everywhere in Xiangyang city.( )
A.numberB.pairC.kindD.piece