Upon arriving at the airport, she realized she had forgotten her passport.

She found a comfortable sit-upon to use during the picnic.

The put-upon employee was forced to stay late every day.

I hit upon a brilliant idea.

Upon hearing the news, she immediately burst into tears.

It is important to act upon the feedback received from customers.

I happened upon a beautiful park while walking in the city.

The approval is conditional upon meeting all the requirements.

I stumbled upon a hidden treasure while hiking in the mountains.

I will call upon my friend tomorrow.