Patience is an important ____ of a happy and rewarding life. After all, some things are worth waiting for. 

The sentence doesn’t make any             , no matter how you read it.

Last night he saw two dark ___enter the building, and then there was the explosion.

For the young, ______ should be showed to their parents, teachers and old people.

There is a(an) ______ that more graduates choose teaching as their permanent careers.