10. By the middle of the 21st century ,
题型：选择题
问题：
10. By the middle of the 21st century , the vast majority of the world’s population ________ in cities rather than in the country.
A．are living
B．will be living
C．have lived
D．will have lived
10. By the middle of the 21st century , the vast majority of the world’s population ________ in cities rather than in the country.
A．are living
B．will be living
C．have lived
D．will have lived