text: Q:
  
  "Had not being able" or "not having been able"?
  
  I'm writing an apology letter for missed class. Which of the following should I use? 
  
  I had not being able to attend the class.
  I not having been able to attend the class.
  
  If both are ungrammatical, is there any other way to express this?
  When I searched for answers, I got more confused. I couldn't find any legitimate solution, and I'm not sure if the sources can be trusted or not. Can anyone help me on this?
  
  A:
  
  If you are writing a letter, and you missed a single class, use:
  
  I'm sorry I was not able to attend class.
  
  If you missed a series of classes, and you have not been back to class yet, and you want to allude to the ongoing practice of missing class, use:
  
  I'm sorry I have not been able to attend class. 
  
  That second sentence might be better if you were unable to attend class for a more prolonged period of time. It sounds like the wording you might have been fishing for.
  
  