Doctors have been researching effect stand-up and other forms of edy have on us.
A. which
B. what
C. whatever
D. whichever
网友回答
A. which
(答案→)B. what
C. whatever
D. whichever
解析：句意：医生一直在研究单口喜剧和其他的喜剧形式对我们有什么影响。这里research后面接的是宾语从句，因为effects前面缺少定语，用what连接宾语从句，which哪个，whatever“凡是…的东西”，whichever“凡是哪个”，都不符合句意，选B。