Not only polluted, but crowded.
A. was the city; were the streets
B. the city was; the streets were
C. was the city; the streets were
D. the city was; were the streets
网友回答
A. was the city; were the streets
B. the city was; the streets were
(答案→)C. was the city; the streets were
D. the city was; were the streets
解析：城市不仅仅是被污染了，而且街上也拥挤。 not only… but also…引导的并列句，前面的分句要倒装，而后面的不倒装。