John and I _____ friends for eight years. We first got to know each other at a Christmas party. But we _____ each other a couple of times before that.
—How was your examination? —It wasn’t very difficult,but it was__________long.
Anyone who has a _________of humor can get along well in__________society.
Doctors are still trying their best to__________the boy for his broken leg.
The United States has become a significant musical _________around the world.
The invention of_________ paper was a great contribution to________human civilization.