It depends on what period (present or past) you are talking about. For example: Are you busy this morning?- You are talking to a person 'this morning' and asking them if they are busy during this morning (present tense). Were you busy this morning? - You are talking to a person and asking them if they were busy during the morning of today. For example, you may be talking to a person 'this afternoon' or 'this evening' about how busy they were 'this morning' Have you been busied this morning? - This is not 'good english'. I would encourage you not to use this in your practice :-)