More patients__________in hospital this year than last year. A.treated B.have treated C.had been treated D.have been treated 答案:Dpatients与treat之间存在被动关系,应使用被动语态,故排除A、B两项;由时间状语this year可判断,应使用现在完成时态,故选D项。暑假期间,小明帮助爸爸干农活(如图所示),爸爸用500N的力拉车,小明用200N的力推车,他们合力的大小是( )A.500NB.700NC.300ND.200N