it look as though they are having so much fun 
(ROOT (S (NP (PRP it)) (VP (VBP look) (SBAR (IN as) (IN though) (S (NP (PRP they)) (VP (VBP are) (VP (VBG having) (NP (ADJP (RB so) (JJ much)) (NN fun)))))))))
(ROOT (S (NP (PRP )) (VP (VBP ) (SBAR (IN ) (IN ) (S (NP (PRP )) (VP (VBP ) (VP (VBG ) (NP (ADJP (RB ) (JJ )) (NN )))))))))