The first conditional is used to talk about possible situations in the future. It connects two actions where one must occur before the other. It uses the present tense for the if-clause and will for the result. For example, "She will go to university if she gets good grades" means it is possible she will go to university depending on her exam results. Other modal verbs like "might", "could", "can", "should", or "may" can also be used in the result to indicate different levels of possibility or certainty.