Anonymous said:
Something had happened there, I don't know what?
Something had happen there, I don't know what?
Comma splice
Something had happened here (Sentence 1)
,
I don't know what (Sentence 2).
Try,
A. Something had happened here
; I don't know what (it was).
B. Something had happened here
. I don't know what (it was).
C. Something had happened here
and I don't know what (it was).