The First Conditional is used to talk about future events that are likely to happen.
Let’s say it’s weekend and you want to have a picnic at the park. The weather is nice but it is forecast to rain in the afternoon. What will you do if it rains?
If it rains (Present Simple), I will watch (Future Simple) TV.
We use the Present Simple tense to talk about a possible future condition.
We use the Future Simple tense to talk about a future possible result.
The First Conditional is used to talk about a real possibility in the future.
eg. If I eat fruit and vegetables I will have be healthy.
Sometimes we can use may, shall or can instead of will.
eg. If it’s snowy we can ski.