Used to ask for permission or to inquire about the possibility of an action, meaning "is it okay?" or "can you?"; literally the "A-not-A" question form of [[可以|可以|ke3 yi3]].

a summer insect cannot talk of ice; one cannot discuss broad matters with persons of narrow experience or limited perspective

too far or too great to be measured in terms of distance; incalculable; immeasurable