-Would you get me a bar of chocolate from the kitchen,dear?-          one?                                        

 All of us found ______ difficult to work out the maths problem.

Charles Darwin, a young man just out of university, knew perfect well that he had to depend on _____ when he set out on a voyage of discovery around the world. 

The old man has expected to see all his children when he was in hospital, but ______ came to see him.

One of the sides of the wood board should be painted yellow, and ________.