China'spopulationisexpectedtoincreasetoabout1.5billioni...

问题详情：

China's population is expected to increase to about 1.5 billion in 2040, ________it will start to decline slowly.

A. where            B. after which         C. on which            D. which

【回答】

B

知识点：定语从句

题型：选择题