A person wearing protective clothing coverings is sitting in front of a microscope.
a person uses a microscope.
Someone in front of a microscope could be the one who uses it.
exists e1 e2 s1 x1 x2 x3 x4 x5 x6.(in(e2,x5) & of(x5,x6) & n_microscope(x6) & n_front(x5) & Actor(e2,x1) & v_sit(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_covering(x3) & of(x3,x4) & n_clothing(x4) & a_protective(s1) & Theme(s1,x3) & (x1 = x2) & n_person(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_use(e1) & n_microscope(x2) & n_person(x1))