they just do it on their own.
1	they	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	3	nsubj	3:nsubj	_
2	just	just	ADV	RB	_	3	advmod	3:advmod	_
3	do	do	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	0:root	_
4	it	it	PRON	PRP	Case=Acc|Gender=Neut|Number=Sing|Person=3|PronType=Prs	3	obj	3:obj	_
5	on	on	ADP	IN	_	7	case	7:case	_
6	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	7	nmod:poss	7:nmod:poss	_
7	own	own	ADJ	JJ	Degree=Pos	3	obl	3:obl:on	SpaceAfter=No
8	.	.	PUNCT	.	_	3	punct	3:punct	_
