A man or older boy is standing up in a blue and white speedboat that's parked in a driveway.
A young boy pretends he's a speed racer in his dad's boat.
In sentence 1 we don't know why the boy is standing n the boat like he is. He may be pretending that he's a speed racer, but sentence 1 doesn't back that up.
exists e2 e1 s1 s2 s3 x1 x2 x3 x4.(in(e1,x2) & in(e2,x4) & n_driveway(x4) & Theme(e2,x3) & v_park(e2) & (x2 = x3) & n_speedboat(x2) & a_white(s3) & Theme(s3,x2) & a_blue(s2) & Theme(s2,x2) & a_up(s1) & Manner(e1,s1) & Actor(e1,x1) & v_stand(e1) & (n_man(x1) | exists s4.(n_boy(x1) & r_more(s4) & a_older(s4) & Theme(s4,x1))))
exists e1 p1 s1 x1 x4 x5.(exists p2 x1.(exists x2 x3.((x1 = x2) & in(x2,x5) & n_racer(x2) & of(x2,x3) & n_speed(x3)) & n_male(x1)) & n_boat(x5) & of(x5,x4) & n_dad(x4) & of(x4,x1) & n_male(x1) & Topic(e1,p1) & Actor(e1,x1) & v_pretend(e1) & n_boy(x1) & a_young(s1) & Theme(s1,x1))