The Smiths went to Ireland last summer. They had visited the United States three years prior. 

I tried to open the door with my key, but someone had already unlocked it.

Samantha panicked when she got on the bus; she had forgotten her bag in the classroom. 

The witch had killed twenty children before the townspeople stopped her.

Crumbs fell out of his pocket; he had stolen a biscuit before going out.

I was worried because I had not seen him for thee days.

The changeling had lived in darkness before he kidnapped the boy.

I was hungry as I had not eaten for two days.