It's wrong [ ]not to write him a letter.[ ]用of sb还是for

It's wrong [ ]not to write him a letter.[ ]用of sb还是for It's wrong ___ not ___ him a letter.A:of me ;to write B:for 是It's wrong of sb to do sth 还是It's wrong for sb to do sth It`s my great honor to write a letter后面用to you还是for you 到底是It's wrong of sb to do sth还是I's wrong for sb to do sth? I think it is wrong __ our advice.A for him not to take B of a letter to sb.还是 a letter for sb. write a letter=write to sb? It's wrong ____ you to do sth.用of还是用for? It's not easy_____________(write)a business letter I write a letter to my pen friend every week It's time for t write a letter to sb.可以吗