The bird flew.

So the cat chased it away.

The bird flew so the car chased it away.

Bob ran down the road.

He fell over.

Bob ran down the road until he fell over.

Owls are nocturnal.

This means they are active at night.

They have exellent eyesight.

Owls are nocturnal, this means they are active at night, they have exellent eyesight.