General
Lab Material
Lab 1
Lab 2
Lab 3
Lab 4
Lab 5
Lab 6

Solution

Replace

np --> det, n.
    
by
np --> det, nbar.
    
Then add
nbar --> n.
nbar --> adj, nbar.
    

Another solution would be to add the rules

np --> det, ap, n.
ap --> adj.
ap --> adj, ap.
    

Back to lab 1.