4 billion for mercury.
( ( ( 4 billion ) ( for mercury ) ) . )
(ROOT (NP (NP (QP (CD 4) (CD billion))) (PP (IN for) (NP (NN mercury))) (. .)))
Mercury cannot be quantified.
( Mercury ( ( ( can not ) ( be quantified ) ) . ) )
(ROOT (S (NP (NNP Mercury)) (VP (MD can) (RB not) (VP (VB be) (VP (VBN quantified)))) (. .)))