It's good to want to work and improve.
George is struggling lately in school, and he is in danger of failing several classes.
George wants to pass his classes so he can graduate.
George finds a tutor and begins studying more, working hard to improve his grades.
George tries to give the minimum possible effort required to pass his classes.
George passes all his classes easily and feels proud to graduate on time.
George does not pass one class and ends up short of the credits needed to graduate on time.