a thing is a threshold because it lies in such and such a position, and its being means its lying in that position, while being ice means having been solidified in such and such a way.
atalasea da nolabait kokatuta dagoelako, eta "izan"ek, hain zuzen ere, "nolabait kokatuta egon" adierazten du, eta "izotza izan"ek, "nolabait kondentsatuta egon".