They don't know if it worked.
1	They	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	4	nsubj	4:nsubj	Discourse=attribution-negative:170->171:0|Entity=(122-organization-giv:act-cf1*-1-ana)
2-3	don't	_	_	_	_	_	_	_	_
2	do	do	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	4	aux	4:aux	_
3	n't	not	PART	RB	Polarity=Neg	4	advmod	4:advmod	_
4	know	know	VERB	VB	VerbForm=Inf	0	root	0:root	_
5	if	if	SCONJ	IN	_	7	mark	7:mark	Discourse=elaboration-additional:171->168:1
6	it	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	7	nsubj	7:nsubj	Entity=(120-object-giv:inact-cf2-1-ana)
7	worked	work	VERB	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	4	ccomp	4:ccomp	SpaceAfter=No
8	.	.	PUNCT	.	_	4	punct	4:punct	_
