write about a teacher who made an unfortunate mistake which caused a student to suffer as a result .

QUESTION: write about a teacher who made an unfortunate mistake which caused a student to suffer as a result .
                  
                   "Please, Miss lee , let David pass so that he can go on to the next grade ." Madam Lim pleaded[恳求］yet again with the teacher as David sat watching the scene unfolding[逐渐展现］before him . He was in secondary two .  Miss Lee , who taught him  English , was in a dilemma . Should she let this boy pass or stick to her original grading of his paper ?  Was the right answer yes or no ? 
                 Flipping through the examination script, Miss Lee realised yet again that even the failing mark of 33 was lenient. David looked down at his shoes, downcast[沮丧] . Miss lee knew that many of the senior teachers would have informed Madam Lim of the impossibility of her request by now .  Yet , Miss lee could not bring herself to do so and wanted to give David a chance despite his recent spate[一连串] of truancy[逃学] . She also dreaded[恐惧] Madam Lim's respond if her request  was refused. Miss lee clung on[坚持] to the hope that David  would be less discourage if  he continued on in secondary 3 . Relenting[心软/终于答应] , she decided to let him pass , trusting Madam lim 's assurances[保证]. 
              David entered secondary3 with the rest of his class. Yet , very quickly, it became clear that he was still at the bottom of the class in English. The experience English teacher, Mrs Tan , did her best to extend help to him through remedial classes. Miss lee also checked his progress[进展] every once in a while. David, on his part , did try to put  in more effort , yet youthful impatience and pride made him feel frustrated when he found that he still could not pass the majority of the assignments easily . 
             Laziness soon took away any progress David had made . Some of the better classmates taunted[嘲笑] his standard of English , which culminated[最终/告终] in a fight after school , leaving all of them wounded. David decided to avoid his English classes like the plague[灾害] . When Madam lim was informed of it  , she was at her wit's end[没有任何办法/困扰]and vented[表达] her exasperation[使烦恼] on her son . In return , David rebelled even more , dropping out of school  entirely . 
           Miss lee made a home visit to Madam lim after learning about David leaving school. Sobbing  Madam lim said sadly , " i  regret asking you to let my son pass . If he had stayed on in secondary2 , maybe he would have been familiar with the other subjects ." 
          As Miss lee had  already realised with painful clarity , she had made a mistake in her judgment . David's future had become  bleaker due to the chain[一连串] of events set off by her in experienced decision . " i am also sorry for agreeing to pass him . I'm so very sorry ..."