They are all forms of water.
1	They	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	4	nsubj	4:nsubj	Discourse=ROOT:21:0|Entity=(5-object-giv:inact-cf1-1-ana)
2	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	4	cop	4:cop	_
3	all	all	ADV	RB	Degree=Pos	4	advmod	4:advmod	Entity=(5-object-giv:act-cf1-2-pred
4	forms	form	NOUN	NNS	Number=Plur	0	root	0:root	_
5	of	of	ADP	IN	_	6	case	6:case	_
6	water	water	NOUN	NN	Number=Sing	4	nmod	4:nmod:of	Entity=(14-substance-new-cf2-1-coref)5)|SpaceAfter=No
7	.	.	PUNCT	.	_	4	punct	4:punct	_
