Nearly 56 percent of Chinese believe that traffic order got even worse after tightened traffic regulations ______at the beginning of 2013.

A．have been adopted

B．were adopted

C．adopted

D．had adopted

场地最小坡度为( )，最大坡度不大于8%时，最有利于排水。

A．0.1%
B．0.2%
C．0.3%
D．0.4%