A dark-skinned child blowing some bubbles using his mouth.
A black boy is blowing spit bubbles.
A dark skinned boy does not determine his nationality.  Black in reference to people is commonly referred to people of dark skin in the United States of America.
exists e1 e2 s1 x1 x2 x3 x4.(a_topic(x1) & for(e1,e2) & Theme(e2,x4) & Actor(e2,x2) & v_use(e2) & n_mouth(x4) & of(x4,x1) & n_male(x1) & Theme(e1,x3) & Actor(e1,x2) & v_blow(e1) & n_bubble(x3) & (x1 = x2) & n_child(x1) & a_dark-skinned(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_blow(e1) & n_bubble(x2) & of(x2,x3) & n_spit(x3) & n_boy(x1) & a_black(s1) & Theme(s1,x1))