A. d-b-a-c-e B. a-c-b-d-e C. b-e-d-a-c D. b-e-a-c-d ----- Nội dung ảnh ----- Lastly, I felt embarrassed in front of my classmates, who all seemed to have done well. One of the most unpleasant experiences I had at school was when I failed a major exam. This experience taught me a valuable lesson about the importance of preparation and hard work. Also, I was worried about how my parents and teachers would react to my poor performance. In the first place, I felt incredibly disappointed in myself for not studying hard enough.