( ( Calculate ( time changes ) ) ( , ( ( create ( graphs ( showing ( distance ( versus time ) ) ) ) ) . ) ) )
(ROOT (S (NP (JJ Calculate) (NN time) (NNS changes)) (, ,) (VP (VB create) (NP (NP (NNS graphs)) (VP (VBG showing) (NP (NP (NN distance)) (PP (IN versus) (NP (NN time))))))) (. .)))
Calculate time changes, create graphs showing distance versus time.
(ROOT (S (NP (NNP Line) (NNS graphs)) (VP (VBP are) (ADJP (RB especially) (JJ useful) (PP (IN for) (S (VP (VBG showing) (NP (NNS changes)) (PP (IN over) (NP (NN time)))))))) (. .)))