you did you see that
( you ( did ( you ( see that ) ) ) )
(ROOT (S (NP (PRP you)) (VP (VBD did) (SBAR (S (NP (PRP you)) (VP (VBP see) (NP (DT that))))))))
No one saw it. 
( ( No one ) ( ( saw it ) . ) )
(ROOT (S (NP (DT No) (NN one)) (VP (VBD saw) (NP (PRP it))) (. .)))