问题补充:
The excellent student, abroad for many years, is on the way back to her own country.
A. to study
B. studying
C. to have studied
D. having studied
答案:
A. to study
B. studying
C. to have studied
(答案→)D. having studied
解析:考查非谓语动词。The excellent student和study之间是主谓关系,且study这一动作发生在主句谓语动词is on the way back to her own country正确,所以要用doing的完成时。选D。