Complete the sentences with the correct forms of the verbs in brackets.

Write one word in each gap.

I heard the doorbell [ ] (to ring) once. Open the door, please.

They saw a stranger [ ] (to climb) through their neighbours' window for some time.

We watched the sun [ ] (to set) over the horizon. It was an amazing experience!

I saw her [ ] (to drop) the vase from her hands.

I heard the rain [ ] (to tap) against the window for hours.