Indicative
Present Indefinite
I happen upon
you happen upon
he/she/it happens upon
we happen upon
you happen upon
they happen upon
Present Continuous
I am happening upon
you are happening upon
he/she/it is happening upon
we are happening upon
you are happening upon
they are happening upon
Present Perfect
I have happened upon
you have happened upon
he/she/it has happened upon
we have happened upon
you have happened upon
they have happened upon
Present Perfect Continuous
I have been happening upon
you have been happening upon
he/she/it has been happening upon
we have been happening upon
you have been happening upon
they have been happening upon
Past Indefinite
I happened upon
you happened upon
he/she/it happened upon
we happened upon
you happened upon
they happened upon
Past Continuous
I was happening upon
you were happening upon
he/she/it was happening upon
we were happening upon
you were happening upon
they were happening upon
Past Perfect
I had happened upon
you had happened upon
he/she/it had happened upon
we had happened upon
you had happened upon
they had happened upon
Past Perfect Continuous
I had been happening upon
you had been happening upon
he/she/it had been happening upon
we had been happening upon
you had been happening upon
they had been happening upon
Future Indefinite
I will happen upon
you will happen upon
he/she/it will happen upon
we will happen upon
you will happen upon
they will happen upon
Future Continuous
I will be happening upon
you will be happening upon
he/she/it will be happening upon
we will be happening upon
you will be happening upon
they will be happening upon
Future Perfect
I will have happened upon
you will have happened upon
he/she/it will have happened upon
we will have happened upon
you will have happened upon
they will have happened upon
Future Perfect Continuous
I will have been happening upon
you will have been happening upon
he/she/it will have been happening upon
we will have been happening upon
you will have been happening upon
they will have been happening upon
Conditional
Conditional Present
I would happen upon
you would happen upon
he/she/it would happen upon
we would happen upon
you would happen upon
they would happen upon
Conditional Present Continuous
I would be happening upon
you would be happening upon
he/she/it would be happening upon
we would be happening upon
you would be happening upon
they would be happening upon
Conditional Perfect
I would have happened upon
you would have happened upon
he/she/it would have happened upon
we would have happened upon
you would have happened upon
they would have happened upon
Conditional Perfect Continuous
I would have been happening upon
you would have been happening upon
he/she/it would have been happening upon
we would have been happening upon
you would have been happening upon
they would have been happening upon