A ()xyz   # Return it
B (x)yz   # Return it
c (xy)z   # Fails: 1==end(B) <= begin(c)==0
d (xyz)   # Fails: 1==end(B) <= begin(d)==0
E x()yz   # Return it
F x(y)z   # Return it
g x(yz)   # Fails: 2==end(F) <= begin(g)==1
H xy()z   # Return it
I xy(z)   # Return it
J xyz()   # Return it