be convenient to do sth.
be convenient for sth/sb
be convenient to sb/ sth
be convenient for sb to do sth.
be convenient to 一般在乎主体的主观感受,比如例句Please come whenever it is convenient to you.
方便的时候,请随时来.中“方便的时候,请随时来.”,就暗含“如果你觉得方便,请随时过来.”
而convenient for一般形容客观存在的便利,比如你说的例句：The area is convenient for transport. “这个地区便于交通运输”是一个客观事实
