( But ( ( at ( absolute zero ) ) ( , ( ( all motion ) ( stops . ) ) ) ) )
(ROOT (S (CC But) (PP (IN at) (NP (JJ absolute) (CD zero))) (, ,) (NP (DT all) (NN motion)) (VP (VBZ stops)) (. .)))
But at absolute zero, all motion stops.
(ROOT (S (NP (NP (DT The) (NN temperature)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (DT all) (JJ molecular) (NN motion)) (VP (VBZ has) (VP (VBN ceased)))))) (VP (VBZ is) (VP (VBN called) (NP (JJ absolute) (NN zero)))) (. .)))