一道英语题，求解，我觉得B和D貌似都可以耶……

A are living
B will be living
C have lived
D will have lived
请解释得详细点;s population____in cities rather then in the country，谢谢By the middle of the 21st century, the vast majority of the world'

B?

B

D，在21世纪中期应该用将来时态

你好！ B，用将来进行时表示一种状态，而D是将来完成时，表示动作已经完成，而live这个词是个延续性动词 如有疑问，请追问。