你们老师误解了这个词组 after this experience，把它理解为在过去的“某次经历之后”，认为是过去的时间，因此把 keeps 改为 kept。其实，它不影响现在的爬山习惯。after this experience 实际不是指“过去时间”，而是让步的含义，译为 “尽管有这个（可怕的）经历”。

两种改法：

His love for mountain climbing is so great that he keeps on climbing mountains even after this experience. 

His love for mountain climbing was so great that he kept on climbing mountains even after this experience.