—How long do you think it will beman can finally solve the problem of cancer?—Well it depe

问题补充：

—How long do you think it will beman can finally solve the problem of cancer?

—Well，it depends

A. when

B. until

C. after

D. before

答案：

A. when

B. until

C. after

(答案→)D. before

解析：考查连词：句意：你认为还要多久人才能最终解决癌症的问题。--那要看情况而定了。这句话用了It will be+一段时间+before从句，意思是“还要多久…才/就….”，选D。