Two natural rock formations are always pointed out on excursions.
( ( Two ( natural ( rock formations ) ) ) ( ( ( are always ) ( ( pointed out ) ( on excursions ) ) ) . ) )
(ROOT (S (NP (CD Two) (JJ natural) (NN rock) (NNS formations)) (VP (VBP are) (ADVP (RB always)) (VP (VBN pointed) (PRT (RP out)) (PP (IN on) (NP (NNS excursions))))) (. .)))
Four other natural rock formations are sometimes pointed out.
( ( Four ( other ( natural ( rock formations ) ) ) ) ( ( ( are sometimes ) ( pointed out ) ) . ) )
(ROOT (S (NP (CD Four) (JJ other) (JJ natural) (NN rock) (NNS formations)) (VP (VBP are) (ADVP (RB sometimes)) (VP (VBN pointed) (PRT (RP out)))) (. .)))