( ( These groups ) ( ( are ( called ( Round Tables ) ) ) . ) )
(ROOT (S (NP (DT These) (NNS groups)) (VP (VBP are) (VP (VBN called) (NP (NNP Round) (NNP Tables)))) (. .)))
These groups are called Round Tables.
(ROOT (S (NP (NP (NNP Group) (CD 13)) (PP (IN of) (NP (DT the) (JJ periodic) (NN table)))) (VP (VBZ is) (ADVP (RB also)) (VP (VBN called) (NP (DT the) (DT the) (NN boron) (NN group)))) (. .)))