问题
单项选择题
Since Jonas Salk came up with his polio vaccine, infantile paralysis has virtually disappeared from the United States.
A．surfaced with
B．raised the price of
C．discovered
D．elevated
答案
参考答案：C
解析：习语辨析。come up with想出，提出，提供；raise the price of抬高……的价格；discover (首次)发现，发觉，找到；因此C为答案。