what 's hard to understand is why anybody picked it up . 
(ROOT (S (SBAR (WHNP (WP what)) (S (VP (VBZ 's) (ADJP (JJ hard)) (S (VP (TO to) (VP (VB understand))))))) (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (NN anybody)) (VP (VBD picked) (NP (PRP it)) (PRT (RP up)))))) (. .)))
(ROOT (S (SBAR (WHNP (WP )) (S (VP (VBZ ) (ADJP (JJ )) (S (VP (TO ) (VP (VB ))))))) (VP (VBZ ) (SBAR (WHADVP (WRB )) (S (NP (NN )) (VP (VBD ) (NP (PRP )) (PRT (RP )))))) (. )))