关于这个问题，有很多原因。一个主要原因是车辆增加的数量远快于道路的建设。另一个主要原因是私家车过多而公交车不够。

There are several reasons for this problem. One of the main reasons is that the number of vehicles is increasing much more rapidly than building of roads.

youdao

有一些主要原因。其中一个原因是……，另一个原因是……，而最经常被强调的原因是…… …

There are some major causes for… One cause is… Another cause is… And the most frequently stressed cause is…

youdao

有一些主要原因。其中一个原因是……，另一个原因是……，而最经常被强调的原因是…… …

There are some major causes for… One cause is… Another cause is… And the most frequently stressed cause is…

youdao