The people were busy reading materials.
The busy people are reading material.
If they are busy reading, they are busy people.
exists e1 p1 x1.(n_people(x1) & exists e2 x2.(Theme(e2,x2) & Actor(e2,x1) & v_read(e2) & n_material(x2)) & Topic(e1,p1) & Actor(e1,x1) & v_busy(e1))
exists e1 s1 x1 x2.(n_people(x1) & a_busy(s1) & Theme(s1,x1) & Theme(e1,x2) & Actor(e1,x1) & v_read(e1) & n_material(x2))