Heisenberg wasn't sure.
1	Heisenberg	Heisenberg	PROPN	NNP	Number=Sing	4	nsubj	4:nsubj	_
2-3	wasn't	_	_	_	_	_	_	_	_
2	was	be	AUX	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	4	cop	4:cop	_
3	n't	not	PART	RB	_	4	advmod	4:advmod	_
4	sure	sure	ADJ	JJ	Degree=Pos	0	root	0:root	SpaceAfter=No
5	.	.	PUNCT	.	_	4	punct	4:punct	_
