( ( ( The first ) ( of ( these classes ) ) ) ( ( ( are ( the ( seven ( SI ( base units ) ) ) ) ) ( for ( ( length ( , ( mass ( , ( time ( , ( temperature ( , ( electric ( current ( , ( luminous ( ( intensity and ) amount ) ) ) ) ) ) ) ) ) ) ) ) ) ( of substance ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ first)) (PP (IN of) (NP (DT these) (NNS classes)))) (VP (VBP are) (NP (DT the) (CD seven) (NNP SI) (NN base) (NNS units)) (PP (IN for) (NP (NP (NN length) (, ,) (NN mass) (, ,) (NN time) (, ,) (NN temperature) (, ,) (JJ electric) (JJ current) (, ,) (JJ luminous) (NN intensity) (CC and) (NN amount)) (PP (IN of) (NP (NN substance)))))) (. .)))
The first of these classes are the seven SI base units for length, mass, time, temperature, electric current, luminous intensity and amount of substance.
(ROOT (S (NP (NP (NNP Time)) (, ,) (NP (NN mass)) (, ,) (NP (NN length)) (, ,) (CC and) (NP (NN temperature))) (VP (VBP are) (VP (VBN considered) (S (VP (TO to) (VP (VB be) (NP (NN base) (NNS units))))))) (. .)))