一个多月之后搜这道题竟然发现我之前的评论。。我决定自己回答自己一波:
文章说的是Yet although the proportion of new cars in Donia's capital city has always been comparatively high, nitrogen dioxide emissions there have showed only an insignificant decline since 1993.言下之意就是首都的排放量不如其他城市多,重点在于排放量少于其他城市,而不是在于在1993年只有一次显著的排放量下降