-Why does the Lake smell terrible? -Because large quantities of water . A. have polluted B. is being polluted C. has been polluted D. have been polluted 答案:D考查动词时态,语态和主谓语一致。根据前一分句可知所填动词表示过去发生的动作对现在产生的影响,时态用现在完成时,动词与主语是被动关系,用被动语态。主语是large quantities of water,其中心词是quantities,是复数,谓语动词用复数,选D。 下列史实按顺序排列正确的是( )①“东方红1号”升天②社会主义制度确立③重返联合国④粉碎“四人帮”⑤加入亚太经合组织⑥“八六三计划”A.①②③④⑤⑥B.②①④③⑥⑤C.②①④③⑤⑥D.②①③④⑥⑤