A singer with a guitar sings into a microphone on stage while the drummer sits behind him.
A singer with an accordion sings into a microphone on stage while the bassist sits in front of him.
An accordion is not a guitar and a bassist is not a drummer.
exists e1 p1 x1 x2 x3 x4 x5.(n_male(x5) & n_drummer(x5) & exists e2.(behind(e2,x5) & Actor(e2,x5) & v_sit(e2)) & while(e1,p1) & on(e1,x4) & n_stage(x4) & into(e1,x3) & n_microphone(x3) & Actor(e1,x1) & v_sing(e1) & with(x1,x2) & n_guitar(x2) & n_singer(x1))
exists e1 p1 x1 x2 x3 x4 x5.(n_male(x5) & n_bassist(x5) & exists e2 x6.(in(e2,x6) & of(x6,x5) & n_front(x6) & Actor(e2,x5) & v_sit(e2)) & while(e1,p1) & on(e1,x4) & n_stage(x4) & into(e1,x3) & n_microphone(x3) & Actor(e1,x1) & v_sing(e1) & with(x1,x2) & n_accordion(x2) & n_singer(x1))