问题
选择题
____ abroad for two years, the two astronauts went back home last year.
A．Educating
B．Educated
C．Having been educated
D．being educated
答案
答案：C
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。