4 billion for mercury.
( ( ( 4 billion ) ( for mercury ) ) . )
(ROOT (NP (NP (QP (CD 4) (CD billion))) (PP (IN for) (NP (NN mercury))) (. .)))
There is four billion of something for mercury.
( There ( ( is ( ( four billion ) ( of ( something ( for mercury ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBZ is) (NP (NP (QP (CD four) (CD billion))) (PP (IN of) (NP (NP (NN something)) (PP (IN for) (NP (NN mercury))))))) (. .)))