Presente Simple
I happen to be free today.
You happen to know the answer.
He happens to be my friend.
She happens to like the same music.
It happens to be true.
We happen to have a meeting.
They happen to be away.
Pasado Simple
I happened to see him yesterday.
You happened to miss the train.
He happened to call while you were out.
She happened to find her old diary.
It happened during the night.
We happened to be at the same concert.
They happened to be there too.
Futuro Simple
I will happen to be in town then.
You will happen to see him tomorrow.
He will happen to be there at the same time.
She will happen to need help.
It will happen eventually.
We will happen to have a spare ticket.
They will happen to meet us there.
Presente Continuo
I am happening to go there now.
You are happening to work on that project.
He is happening to read that book.
She is happening to cook dinner.
It is happening right now.
We are happening to be busy at the moment.
They are happening to play outside.
Pasado Continuo
I was happening to walk by then.
You were happening to study for the exam.
He was happening to clean the house.
She was happening to talk to him.
It was happening to rain all day.
We were happening to think about moving.
They were happening to watch a movie.