问题
选择题
In the past half-century, average incomes _______ quickly in developed countries, yet happiness levels have remained almost the same.
A．have risen
B．had risen
C．rose
D．rise
答案
答案：A
考查时态。根据时间状语In the past half-century在过去的半个世纪，可知用现在完成时，选A。