s(Number,s(Np,Vp)) -->
	np(Number,Np),
	vp(Number,Vp).

np(Number,np(Art,N))  -->
	art(Number,Art),n(Number,N).

vp(Number,vp(Verb)) --> 
	v(Number,Verb).

art(s3,art(a)) --> [a].
art(p3,art(the)) --> [the].
art(s3,art(the)) --> [the].


n(s3,n(dog)) --> [dog].
n(p3,n(dogs)) --> [dogs].

v(s3,v(cried))  --> [cried].
v(p3,v(cried))  --> [cried].