仁寿黑龙滩镇最新消息:Researches___all over the world into the possible cause of cancerinthepastfewyear.
来源:百度文库 编辑:高考问答 时间:2024/05/10 12:49:23
A weremadeB hadbeen madeC havebeenmade
C. have been made.
理由: 1 现在完成式
2 被动语
3 researches是复数,用have.
选b因为in the past few year 是过去完成时态的标志
A
表示持续性