﹣﹣﹣We should try to devote（献身于）ourselves to our country like Yuan Longping.

﹣﹣﹣I think so.He still worked on the research into agriculture（农业）at the age of _________.（　　）

A．	eighties	B．	eightieth
C．	eighty	D．	eighty﹣year﹣old