( ( ( Solution ( -LRB- ( a -RRB- ) ) ) ( ( A liquid ) ( containing ( dissolved substances ) ) ) ) . )
(ROOT (NP (NP (NP (NN Solution)) (PRN (-LRB- -LRB-) (X (SYM a)) (-RRB- -RRB-))) (NP (NP (DT A) (NN liquid)) (VP (VBG containing) (NP (JJ dissolved) (NNS substances)))) (. .)))
Solution (a) A liquid containing dissolved substances.
(ROOT (S (NP (DT A) (NN solution)) (VP (VBZ forms) (SBAR (WHADVP (WRB when)) (S (NP (CD one) (NN substance)) (VP (VBZ dissolves) (PP (IN into) (NP (DT another))))))) (. .)))
A solution forms when one substance dissolves into another.