Some researchers believe that there is no doubt a cure for AIDS will be found.A. whichB. t

问题补充：

Some researchers believe that there is no doubt a cure for AIDS will be found.

A. which

B. that

C. what

D. whether

答案：

A. which

(答案→)B. that

C. what

D. whether

解析：考查同位语从句。doubt作名词，用在否定句中，后面是doubt的同位语从句，用that引导。所以选B。