【正确答案】Dear Sir or Madam,
{{U}}I am writing to you to complain about{{/U}} the poor health in the corridor of dormitory building 8. In the recent weeks, the school cleaners didn't sweep the floor in time. The stairs were very dirty and I almost slipped yesterday. {{U}}What's more{{/U}}, some waste baskets have been piled on the second floor, which brings inconvenience for the students.
{{U}}Firstly, I would like to suggest{{/U}} that the cleaners can sweep the floor according to the regulations. {{U}}Secondly{{/U}}, the cleaner can clean the stairs after lunch and supper because students may throw some litters in the steps of the stairs. {{U}}Lastly, Please{{/U}}collect the waste baskets {{U}}as soon as possible{{/U}}.
{{U}}Many thanks for considering my comments, and I hope these suggestions will be useful for you{{/U}}.