Fill in each blank with an appropriate preposition:
It’s very difficult to find work _____________________the moment.
This service is free _____________________charge.
In many ways you take _____________________your mother.
This computer is still _____________________guarantee.
Money is not essential _____________________happiness.
She is ______________________far the best teacher I have ever had.
Parents are naturally anxious ______________________their children.
I’m sure you will succeed ______________________this entrance test.
We try to prevent people _____________________littering.
I’m going to complain to the principal ____________________this.