A senior citizen in a hospital bed.
a person in a bed
A senior citizen in a hospital bed means there is a person (senior citizen) in a bed (hospital bed).
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & n_bed(x2) & of(x2,x3) & n_hospital(x3) & n_citizen(x1) & a_senior(s1) & Theme(s1,x1))
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_bed(x2) & n_person(x1))