private cars bring us convenience, they also cause more traffic accidents and pollution.
A. While
B. As
C. If
D. Since
网友回答
(答案→)A. While
B. As
C. If
D. Since
解析：考查连词：A. While当…时候，虽然，然而，B. As当…时候，因为，正如C. If如果，D. Since
自从，既然，句意：虽然私家车给我们带来了方便，也造成交通事故和污染。选A。