Explanation:
We use subjunctive when:
We want to express a wish.
We want to express an emotion.
We want to express suggestion.
We want to express a command.
We want to express a condition.
We want to express a doubt.
We want to express something unknown.
Etc.
Examples:
Quiero que no tengas novia.
I wish you don’t have a girlfriend.
Siento que tengas frio.
I feel like you are cold.
Tal vez tenga frio.
Sometimes I’m cold.
Es bueno que...
It’s good to...
Es importante que....
It’s important to...
