( a ) strong piece of work . 
(ROOT (NP (FRAG (-LRB- -LRB-) (LS a) (-RRB- -RRB-) (JJ strong) (NN piece)) (PP (IN of) (NP (NN work))) (. .)))
(ROOT (NP (FRAG (-LRB- ) (LS ) (-RRB- ) (JJ ) (NN )) (PP (IN ) (NP (NN ))) (. )))