John _____ knowledge of radio just by staying around the radio station.
_____ all the inventions have in common is ______ they have succeeded.
Last term our maths teacher set so difficult an examination problem _____ none of us worked out.
A cook will be immediately fired if he is found ______in the kitchen.
It was with great joy ______ he received the news that his lost daughter had been found.
Henry can’t attend the party _______ at Tom’s house at present because he is preparing the speech at the party _______ at Marie’s house tomorrow.