Because bob ran down the road, he fell over.

The thunder roared, so the hobbits hid.

Since Bilbo slept in a cave, the goblins attacked.

The cart came to a wheezing halt, as soon as Gandalf strode into the hobbit hole.

Jim was interested in the idea, so he rang his friend.

Owls are nocturnal and this means they are active at night, so they have excellent eyesight.