Said as either "Now see what happend was.." or "what had happen was..". A phrase used when someone is asked something that they do not know the answer, mostly used when their homework is not turned in.
Said as "What happend was.." or "What had happen was..". A phrase that is said when some one is asked something and they do not know the answer; an excuse followed by the explanation of the situation or by the asker interrupting the person's reply.