( ( Because ( naphthalene ( can ( ( catch fire ) easily ) ) ) ) ( , ( ( modern mothballs ) ( ( ( use 1,4-dichlorobenzene ) instead ) . ) ) ) )
(ROOT (S (SBAR (IN Because) (S (NP (NN naphthalene)) (VP (MD can) (VP (VB catch) (NP (NN fire)) (ADVP (RB easily)))))) (, ,) (NP (JJ modern) (NNS mothballs)) (VP (VBP use) (NP (JJ 1,4-dichlorobenzene)) (ADVP (RB instead))) (. .)))
Because naphthalene can catch fire easily, modern mothballs use 1,4-dichlorobenzene instead.
(ROOT (S (NP (NNS Naphthalens)) (VP (VBZ is) (NP (NP (DT a) (NN chemical)) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (ADVP (RB commonly)) (VP (VBN used) (PP (IN in) (NP (NNS mothballs))))))))) (. .)))