( ( ( ( ( It ( ( combines spontaneously ) ( with ( ( most ( other elements-exceptions ) ) ( are ( ( ( ( ( ( ( chlorine , ) nitrogen ) , ) oxygen ) , ) and ) ( ( the ( so-called ( inert gases ) ) ) ( -LRB- ( ( ( helium , ) ( neon ( , ( argon ( , ( krypton ( , ( xenon ( , ( and radon ) ) ) ) ) ) ) ) ) ) -RRB- ) ) ) ) ) ) ) ) ) , ) but ) ( it ( even ( ( combines ( with ( most ( of these ) ) ) ) ( when heated ) ) ) ) ) . )
(ROOT (S (S (NP (PRP It)) (VP (VBZ combines) (ADVP (RB spontaneously)) (SBAR (IN with) (S (NP (RBS most) (JJ other) (NNS elements-exceptions)) (VP (VBP are) (NP (NP (NN chlorine)) (, ,) (NP (NN nitrogen)) (, ,) (NP (NN oxygen)) (, ,) (CC and) (NP (NP (DT the) (JJ so-called) (NN inert) (NNS gases)) (PRN (-LRB- -LRB-) (NP (NP (NNP helium)) (, ,) (NP (NN neon) (, ,) (NN argon) (, ,) (NN krypton) (, ,) (NN xenon) (, ,) (CC and) (NN radon))) (-RRB- -RRB-))))))))) (, ,) (CC but) (S (NP (PRP it)) (ADVP (RB even)) (VP (VBZ combines) (PP (IN with) (NP (NP (JJS most)) (PP (IN of) (NP (DT these))))) (SBAR (WHADVP (WRB when)) (S (VP (VBN heated)))))) (. .)))
It combines spontaneously with most other elements-exceptions are chlorine, nitrogen, oxygen, and the so-called inert gases (helium, neon, argon, krypton, xenon, and radon), but it even combines with most of these when heated.
(ROOT (S (NP (NNP Nitrogen) (, ,) (NNP oxygen) (CC and) (NNP argon)) (VP (VBP are) (NP (NP (DT the) (CD three) (JJS most) (JJ common) (NNS elements)) (PP (IN in) (NP (NP (DT the) (NN air)) (SBAR (S (NP (PRP we)) (VP (VB breathe)))))))) (. .)))