As you can see, the number of cars on roads ________ rising these days.
A.was keeping
B.keep
C.keeps
D.were keeping
网友回答
C解析the number of+可数名词的复数作主语时,中心词是number,谓语动词用单数;a number of+可数名词的复数作主语时,中心词是of后面的名词,谓语动词用复数。时间状语是these days,因此不可能用过去进行时,故排除A和D项;主语是the number of cars,其中心词是number,单数,故谓语动词用单数。