What happened?
1	What	what	PRON	WP	PronType=Int	2	nsubj	2:nsubj	_
2	happened	happen	VERB	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	0	root	0:root	SpaceAfter=No
3	?	?	PUNCT	.	_	2	punct	2:punct	_
