( Bosons ( ( ( ( may ( be ( classified ( as ( ( gauge bosons ) ( -LRB- ( ( carriers ( of ( the ( four ( fundamental forces ) ) ) ) ) -RRB- ) ) ) ) ) ) ) or ) mesons ) . ) )
(ROOT (S (NP (NNS Bosons)) (VP (VP (MD may) (VP (VB be) (VP (VBN classified) (PP (IN as) (NP (NP (NN gauge) (NNS bosons)) (PRN (-LRB- -LRB-) (NP (NP (NNS carriers)) (PP (IN of) (NP (DT the) (CD four) (JJ fundamental) (NNS forces)))) (-RRB- -RRB-))))))) (CC or) (VP (VBZ mesons))) (. .)))
Bosons may be classified as gauge bosons (carriers of the four fundamental forces) or mesons.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD four) (NNS types)) (PP (IN of) (NP (NNS bosons))))) (. .)))