(2013·新课标Ⅱ卷)--I'm sorry I made a mistake! -- Nobody is perfect.
-Everyone says you are a good student. You are never late for school,are you? -_______.
_____ 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.