who are enthusiastic about something and then 
(ROOT (SBAR (SBAR (WHNP (WP who)) (S (VP (VBP are) (ADJP (JJ enthusiastic) (PP (IN about) (NP (NN something))))))) (CC and) (ADVP (RB then))))
(ROOT (SBAR (SBAR (WHNP (WP )) (S (VP (VBP ) (ADJP (JJ ) (PP (IN ) (NP (NN ))))))) (CC ) (ADVP (RB ))))