题目

The old couple have been married for 40 years and never once ________ with each other. A. they had quarrelled   B. they have quarrelled C. have they quarrelled  D. had they quarreled 答案：C 解析: C。由否定意义的词never once开头，句子用部分倒装；前一并列分句已经提示要用现在完成时态。下列不属于对种群特征描述的是（　　） A、某市近三年入户的人口约为31万人，约占总人口的5%B、蒲公英杂乱无章地分布在操场上C、某池塘生活了约150种生物D、某市男性公民与女性公民的比例为1：1.5