imagine acting that could be any flatter 
(ROOT (S (VP (VB imagine) (NP (NP (NN acting)) (SBAR (WHNP (DT that)) (S (VP (MD could) (VP (VB be) (ADJP (DT any) (JJR flatter))))))))))
(ROOT (S (VP (VB ) (NP (NP (NN )) (SBAR (WHNP (DT )) (S (VP (MD ) (VP (VB ) (ADJP (DT ) (JJR ))))))))))