The fruits should be treated with lemon juice when sliced to prevent oxidation.
The potato is slowly cooked with butter.
The vegetables should be cooked with lemon juice, not butter.
exists e1 p1 x1.(n_fruit(x1) & exists e2 e3 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 e1 s1 x1 x2.(n_potato(x1) & a_slowly(s1) & Manner(e1,s1) & with(e1,x2) & n_butter(x2) & Theme(e1,x1) & v_cook(e1))