Professor Lee failed many times but he found a good way to solve the problem.A. graduallyB

问题补充：

Professor Lee failed many times but he found a good way to solve the problem.

A. gradually

B. entirely

C. finally

D. frequently

答案：

A. gradually

B. entirely

(答案→)C. finally

D. frequently

解析：此处gradually 渐渐地；entirely整个地；finally最终；frequently频繁地。句意：李教授失败了很多次但他最后找到了一个解决问题的好方法。根据句意选C。