We use the conditionals to describe and speculate about something that might happen. Most of the phrases (clauses) that use conditional verb tenses contain the term ‘If’.
It is generally true and occurs at the time or speaking or is habitual.
Verb tenses in both parts of the clauses are in present simple.
Example: If it rains, the grass gets wet.
When it rains, the grass gets wet.
To refer to the real or highly posible situation occurring in the present.
Example: If it rains, we will stay at home.