Within a few years China well have the most advanced railway industry in the world.A. wil

问题补充：

Within a few years China well have the most advanced railway industry in the world.

A. will

B. can

C. must

D. may

答案：

A. will

B. can

C. must

(答案→)D. may

解析：句意：在几年中，中国很有可能有世界上最先进的铁路行业。和well搭配用may，may well主要用于加强推测的语气，表示具有较大的可能性。其他三个情态动词不能和well搭配，所以选D。