Should have done research before you left.
1	Should	should	AUX	MD	VerbForm=Fin	3	aux	3:aux	_
2	have	have	AUX	VB	VerbForm=Inf	3	aux	3:aux	_
3	done	do	VERB	VBN	Tense=Past|VerbForm=Part	0	root	0:root	_
4	research	research	NOUN	NN	Number=Sing	3	obj	3:obj	_
5	before	before	SCONJ	IN	_	7	mark	7:mark	_
6	you	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	7	nsubj	7:nsubj	_
7	left	leave	VERB	VBD	Mood=Ind|Number=Sing|Person=2|Tense=Past|VerbForm=Fin	3	advcl	3:advcl:before	SpaceAfter=No
8	.	.	PUNCT	.	_	3	punct	3:punct	_
