( ( ( ( Watch ( as ( two ( atoms bond ) ) ) ) and ) ( ( give off ) energy ) ) . )
(ROOT (S (VP (VP (VB Watch) (PP (IN as) (NP (CD two) (NNS atoms) (NN bond)))) (CC and) (VP (VB give) (PRT (RP off)) (NP (NN energy)))) (. .)))
Watch as two atoms bond and give off energy.
(ROOT (S (NP (NN Bond) (NN energy)) (VP (VBZ holds) (NP (NNS atoms)) (ADVP (RB together))) (. .)))
Bond energy holds atoms together.