( ( A solution ) ( ( is ( ( a ( uniform mixture ) ) ( of ( two substances ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN solution)) (VP (VBZ is) (NP (NP (DT a) (JJ uniform) (NN mixture)) (PP (IN of) (NP (CD two) (NNS substances))))) (. .)))
A solution is a uniform mixture of two substances.
(ROOT (S (NP (DT All) (NNS solutions)) (VP (VBP contain) (NP (QP (IN at) (JJS least) (CD two)) (NNS substances))) (. .)))