( There ( ( is ( ( ( ( a loss ) ( of ( 3 pi-bonds ) ) ) and ) ( ( a gain ) ( of ( ( ( one ( new pi-bond ) ) and ) ( two ( new ( sigma bonds ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBZ is) (NP (NP (NP (DT a) (NN loss)) (PP (IN of) (NP (CD 3) (NNS pi-bonds)))) (CC and) (NP (NP (DT a) (NN gain)) (PP (IN of) (NP (NP (CD one) (JJ new) (NN pi-bond)) (CC and) (NP (CD two) (JJ new) (NN sigma) (NNS bonds))))))) (. .)))
There is a loss of 3 pi-bonds and a gain of one new pi-bond and two new sigma bonds.
(ROOT (S (NP (DT A) (JJ double) (NN bond)) (VP (VBZ consists) (PP (IN of) (NP (NP (CD one) (NN sigma) (NN bond)) (CC and) (NP (CD one) (NN pi) (NN bond))))) (. .)))