by which year 和in which year___year will the world's population r_英语解答

by which year 和in which year
___year will the world's population reach 6 billion.
A by which
B in which

人气：354 ℃　时间：2020-04-10 11:15:00

解答

by,应该选A.意思是直到哪一年世界人口会达到60亿.
而in which的意思是一年内的人口达到60亿,想想都不可能.