A motorcyclist drives up the side of a green mountain while another bike remains stationary.
A motorcyclist wearing a helmet drove up the side of a green mountain while another cyclist stayed behind because he didn't feel good.
Not all motorcyclist is wearing a helmet.  Just because a motorcyclist drives up the side of a green mountain while another bike remains stationary does not mean another cyclist stayed behind because he didn't feel good.
exists e1 p1 s1 s2 x1 x2 x3 x4.(n_bike(x4) & n_side(x2) & exists e2 p2 x5.(exists s3.(Theme(s3,x5) & a_stationary(s3)) & Topic(e2,p2) & Actor(e2,x5) & v_remain(e2) & n_bike(x5) & -(x5 = x4)) & while(e1,p1) & a_up(s2) & Manner(e1,s2) & Theme(e1,x2) & Actor(e1,x1) & v_drive(e1) & of(x2,x3) & n_mountain(x3) & a_green(s1) & Theme(s1,x3) & n_motorcyclist(x1))
exists e1 e2 p1 s1 s2 x1 x2 x3 x4 x5 x6.(n_male(x4) & n_cyclist(x6) & n_side(x4) & exists e3 p2 s3 x7.(-exists e4 p3.(exists s4.(Theme(s4,x4) & a_good(s4)) & Topic(e4,p3) & Actor(e4,x4) & v_feel(e4)) & because(e3,p2) & a_behind(s3) & Manner(e3,s3) & Actor(e3,x7) & v_stay(e3) & n_cyclist(x7) & -(x7 = x6)) & while(e2,p1) & a_up(s2) & Manner(e2,s2) & Theme(e2,x4) & Actor(e2,x1) & v_drive(e2) & of(x4,x5) & n_mountain(x5) & a_green(s1) & Theme(s1,x5) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_helmet(x3) & (x1 = x2) & n_motorcyclist(x1))