farmers are performing their agriculture during the day.
There are no crops to tend to.
Farmers cannot be performing their agriculture if there are no crops.
exists e1 x1 x2 x3.(n_day(x3) & during(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_perform(e1) & n_agriculture(x2) & of(x2,x1) & n_thing(x1) & n_farmer(x1))
exists p1 x1.-exists p2 x2.((x1 = x2) & Topic(x2,p2) & exists e2 e1.(Topic(e2,e1) & Actor(e2,x2) & v_tend(e2) & Actor(e1,x2) & v_to(e1)) & n_crop(x2))