4. 2. 9. 8. 6.
once again is a number less than four.
( z0 number :quant ( z1 less-than :op 4 ) :mod ( z2 again :mod ( z3 once ) ) )
(z0 / number
    :quant (z1 / less-than
               :op1 4)
    :mod (z2 / again
             :mod (z3 / once)))
once again is a number less than four .
z2 :mod z3
z0 :mod z2
z0 :quant z1
z1 :op1 0