אֵפוֹ ʼêphôw (H645)

strictly a demonstrative particle, here; but used of time, now or then

1) then, now, so 1a) (who) then, (what) then (with interrog) 1b) then (with imperative-i.e. know then) 1c) if...then (with adv)

or אֵפוֹא; from פֹּה (H6311);