Ответ:

After they saw the Tower, they went to Westminster Abbey.

He asked me which animals I had seen in Africa.

After Columbus discovered America, he returned to Spain.

Before they moved to Liverpool, they had sold everything.

After he had worked very hard, he opened the box after she had fallen ill.

She found the key.

They went to a restaurant after they had sailed.

Before they started the party, they had invited some friends.

After she had washed the curtains, she cleaned the windows.

They went for a sightseeing tour after the bus had arrived.

After he finished school, he worked for a magazine.