( Stress ( ( is ( ( the force ) ( applied ( to ( a body ) ) ) ) ) . ) )
(ROOT (S (NP (NN Stress)) (VP (VBZ is) (NP (NP (DT the) (NN force)) (VP (VBN applied) (PP (TO to) (NP (DT a) (NN body)))))) (. .)))
Stress is the force applied to a body.
(ROOT (S (NP (NP (DT The) (NN force)) (VP (VBN applied) (PP (TO to) (NP (DT an) (NN object))))) (VP (VBZ is) (VP (VBN called) (NP (NN stress)))) (. .)))