【名词&注释】
城市道路(urban road)、化油器(carburetor)、作用力(force)、制动器制动、喷油量(injection quantity)、真空度降低(loss of machine of vacuum)
[单选题]化油器主供油装置利用空气渗入主喷管,以造成主量孔处真空度降低(loss of machine of vacuum),使喷油管()。
A. A、喷油量(injection quantity)减少
B. B、喷油量(injection quantity)增加
C. C、喷油量(injection quantity)中断
D. D、真空度降低(loss of machine of vacuum)