上网查询两种结果都有：
如：
With days passing by common people in Bangladesh are getting more and more unconcerned about state decisions.
孟加拉：The New Nation报社*评
That's why no wonder few people of Iowa and New Hampshire could not decided yet since as days passing by,they are seeing Hillary's devotion,……
摘自：华*盛顿*邮报
而且从内容上看,都没有什么差别,都是“随着时间的流逝.”的意思.因此,两种说法都是对的,用哪个只是取决于作者的偏好而已.