Once Shakespeare mastered traditional blank verse, he began to interrupt and vary its flow.
1	Once	once	SCONJ	CS	_	3	mark	_	_
2	Shakespeare	Shakespeare	PROPN	SP	_	3	nsubj	_	_
3	mastered	master	VERB	V	Mood=Ind|Person=3|Tense=Past|VerbForm=Fin	9	advcl	_	_
4	traditional	traditional	ADJ	A	Degree=Pos	6	amod	_	_
5	blank	blank	ADJ	A	Degree=Pos	6	amod	_	_
6	verse	verse	NOUN	S	Number=Sing	3	obj	_	SpaceAfter=No
7	,	,	PUNCT	FF	_	3	punct	_	_
8	he	he	PRON	PE	Gender=Masc|Number=Sing|Person=3|PronType=Prs	9	nsubj	_	_
9	began	begin	VERB	V	Mood=Ind|Person=3|Tense=Past|VerbForm=Fin	0	root	_	_
10	to	to	PART	PART	_	11	mark	_	_
11	interrupt	interrupt	VERB	V	VerbForm=Inf	9	xcomp	_	_
12	and	and	CCONJ	CC	_	13	cc	_	_
13	vary	vary	VERB	V	Mood=Ind|Number=Plur|Tense=Pres|VerbForm=Fin	11	conj	_	_
14	its	its	DET	AP	Number=Sing|Poss=Yes|PronType=Prs	15	nmod:poss	_	_
15	flow	flow	NOUN	S	Number=Sing	13	obj	_	SpaceAfter=No
16	.	.	PUNCT	FS	_	9	punct	_	_
