abroad for two years, the two astronauts went back home last year.
A. Educating
B. Educated
C. Having been educated
D. being educated
网友回答
A. Educating
B. Educated
(答案→)C. Having been educated
D. being educated
解析：考查非谓语动词。句中逻辑主语the two astronauts与educate为被动关系，根据for two years，可知用完成时，选C。