--- I drove to Zhuhai for the air show last week.--- Is that ____ you had a few days off?

Although he had only entered the contest for fun, _________ he won first prize. 

________ Mr. Smith was the last man I wanted to see, I did all in my power to help him.

A man does not know the difficulty of anything_________ he does it personally.

_______ surprised me most was _______ such a little girl of seven could play the piano so well.