Today the American doctor is one of the foremost heart-transplant surgeons in the world _

外语类 专四 已帮助 人

Today the American doctor is one of the foremost heart-transplant surgeons in the world, ______tens of such operations each year.

A.to perform

B.performing

C.to performing

D.perform

请帮忙给出正确答案和分析,谢谢!

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