It was difficult to tell exactly _______ the saying began, but it is possible that it was in the theatre or movie industry.
With the professor's help, there is no doubt ______ our project is meant for will work out successfully.
My father ______ my brother to drive, but my brother wanted to pick ______ the knowledge of the computer during his spare time.
Before he went abroad, he spent as much time as he ______ English.
Even if you are an experienced teacher, you sometimes ______ make some mistakes.
We should know that we can only reach the top if we are ready to ______ and learn from failure.