1. Happened
What happened?
By the way, what happened to the money I lent you?
Now that you mention it, what happened to that man who used to work here?
The police made the witness explain in detail how the accident had happened.
Whatever happened to acid rain? You don't hear about it in the news anymore.
It all happened so fast, I can't really explain it.
So much has happened. It's as if the whole world is flipped upside down.
If something had happened last night, I think I would have heard it.
If he had been careful then, the terrible accident would not have happened.
Almost all of the passenger in the bus were asleep when the accident happened.
Don't come to me now with that. You should have said something when it originally happened.
What does what happened last night have to do with what's happening today?
Much of what they wrote about never happened.
What's wrong with telling Tom what happened?
Nothing out of the ordinary happened on our trip.