The fruits should be treated with lemon juice when sliced to prevent oxidation.
The fruits are apples
sentence one does not say the fruits are apples.
exists e1 p1 x1.(n_fruit(x1) & exists e3 e2 p2 x2 x3.(when(e2,e3) & Recipient(e3,p2) & Topic(e3,x1) & v_slice(e3) & exists e4 x4.(Theme(e4,x4) & Actor(e4,x1) & v_prevent(e4) & n_oxidation(x4)) & with(e2,x2) & n_juice(x2) & of(x2,x3) & n_lemon(x3) & Theme(e2,x1) & v_treat(e2)) & Topic(e1,p1) & Actor(e1,x1) & v_should(e1))
exists p1 x1.(n_fruit(x1) & exists x2.((x1 = x2) & n_apple(x2)))