( ( Knowing ( that ( atoms ( are neutral ) ) ) ) ( , ( Thomson ( ( postulated ( that ( there ( must ( ( be ( a ( positive charge ) ) ) ( as well ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (VBG Knowing) (SBAR (IN that) (S (NP (NNS atoms)) (VP (VBP are) (ADJP (JJ neutral))))))) (, ,) (NP (NNP Thomson)) (VP (VBD postulated) (SBAR (IN that) (S (NP (EX there)) (VP (MD must) (VP (VB be) (NP (DT a) (JJ positive) (NN charge)) (ADVP (RB as) (RB well))))))) (. .)))
Knowing that atoms are neutral, Thomson postulated that there must be a positive charge as well.
(ROOT (S (NP (NNS Atoms)) (VP (VBP carry) (NP (DT a) (JJ neutral) (NN charge))) (. .)))