The man is talking into the microphone while playing the guitar.
The man is introducing a song he just wrote.
The man is talking and playing the guitar, but no way to know he is introducing a song he just wrote, or that he has written any songs.
exists e1 e2 x1 x2 x3.(n_guitar(x3) & n_microphone(x2) & n_man(x1) & while(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_play(e2) & into(e1,x2) & Actor(e1,x1) & v_talk(e1))
exists e2 e1 s1 x1 x2 x3.(n_male(x1) & n_man(x1) & Theme(e2,x2) & Actor(e2,x1) & v_introduce(e2) & a_just(s1) & Manner(e1,s1) & Theme(e1,x3) & Actor(e1,x1) & v_write(e1) & (x2 = x3) & n_song(x2))