Make sure there are plenty of litter boxes that are cleaned often.
1	Make	make	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	0:root	_
2	sure	sure	ADJ	JJ	Degree=Pos	1	xcomp	1:xcomp	_
3	there	there	PRON	EX	_	4	expl	4:expl	_
4	are	be	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	2	ccomp	2:ccomp	_
5	plenty	plenty	NOUN	NN	Number=Sing	4	nsubj	4:nsubj	_
6	of	of	ADP	IN	_	8	case	8:case	_
7	litter	litter	NOUN	NN	Number=Sing	8	compound	8:compound	_
8	boxes	box	NOUN	NNS	Number=Plur	5	nmod	5:nmod:of|11:nsubj:pass	_
9	that	that	PRON	WDT	PronType=Rel	11	nsubj:pass	8:ref	_
10	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	11	aux:pass	11:aux:pass	_
11	cleaned	clean	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	8	acl:relcl	8:acl:relcl	_
12	often	often	ADV	RB	_	11	advmod	11:advmod	SpaceAfter=No
13	.	.	PUNCT	.	_	1	punct	1:punct	_
