This is the very letter ____came last night.

 I know only a little about this matter; you may ask ____ knows better than I.

 This is the school ____ we visited three days ago.

This is the factory ____ we worked a year ago.

Nearby were two canoes ____ they had come to the island.

Jack is pleased with ____ you have given him and all ____ you have told him.

 Do you work near the building ____ colour is yellow?

Is this school ____ we visited three years ago?

 How many students are there in your class ____ homes are in the country?

Alice received an invitation from her boss, ____ came as a surprise.