If you find English grammar hard, you'll have to study a lot.
If I give you a hand with that job, we'll finish faster.
If you're nice to people, they'll be nice to you.
If it rains later, we'll get wet.
I'm going to be angry if you're late again.
If I have time, I'll come over later.
The situation will be hopeless if I don't speak to you right now.