If you don’t study hard, you won’t pass the exam. (якщо не)
Unless you study hard, you won’t pass the exam.
I won't call him if he doesn't apologize first. (якщо не)
I won't call him unless he apologize first
If you follow the instructions, the machine will work. (за умови, що - офіційно)
Provided that you follow the instructions, the machine will work