x1 answers/replies to/responds to person/object/event/situation/stimulus x2 with response x3.
x3 also answer/reply. If x2 is a person/object, it will usually require "tu'a" indicating that the reply/response is to that person/object doing something. "tu'a" may not be needed if the person/object itself is the stimulus, rather than something it is doing. See also cusku, preti, nabmi, danfu, frati, cpedu.