( It ( ( ( is uncommon ) ( only ( because ( it ( ( combines ( so easily ) ) ( with ( other ( common elements ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (ADJP (JJ uncommon)) (SBAR (RB only) (IN because) (S (NP (PRP it)) (VP (VBZ combines) (ADVP (RB so) (RB easily)) (PP (IN with) (NP (JJ other) (JJ common) (NNS elements))))))) (. .)))
It is uncommon only because it combines so easily with other common elements.
(ROOT (S (NP (JJ Reactive) (NNS elements)) (VP (VBP are) (ADJP (JJ able) (S (VP (TO to) (VP (VB combine) (ADVP (RBR more) (RB easily)) (PP (IN with) (NP (JJ other) (NNS elements)))))))) (. .)))