Professor Lee failed many times but he found a good way to solve the problem.
A. gradually
B. entirely
C. finally
D. frequently
网友回答
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。