问题
选择题
— The teacher asked us ________________
A. What the bad effect of pollution are.
B. What were the bad effect of pollution.
C. What the bad effect of pollution were.
答案
：C
：此题重点考查宾语从句的时态和语序问题，无论哪种句式结构充当宾语从句都要用陈述句语序，从句的时态要和主句的时态保持一致。因主句的谓语动词是过去式从句的谓语动词也要用相应的过去时态。