if you go , pack your knitting needles . 
(ROOT (S (SBAR (IN if) (S (NP (PRP you)) (VP (VBP go)))) (, ,) (VP (VB pack) (NP (PRP$ your) (NN knitting) (NNS needles))) (. .)))
(ROOT (S (SBAR (IN ) (S (NP (PRP )) (VP (VBP )))) (, ) (VP (VB ) (NP (PRP$ ) (NN ) (NNS ))) (. )))