Conditional

The structure of a first conditional sentence:
A first conditional sentence consists of two clauses, an "if" clause and a main clause:

if clause	main clause
If you study hard,	you will pass the test.

If the "if" clause comes first, a comma is usually used. If the "if" clause comes second, there is no need for a comma:
A first conditional sentence consists of two clauses, an "if" clause and a main clause:

main clause	if clause
you will pass the test	If you study hard.

We are talking about the future. We are thinking about a particular condition or situation in the future, and the result of this condition. There is a real possibility that this condition will happen. For example, it is morning. You are at home. You plan to play tennis this afternoon. But there are some clouds in the sky. Imagine that it rains. What will you do?

IF	Condition	Result
	Simple Present	WILL *base verb*
If	it rains	I will stay at home.

Notice that we are thinking about a future condition. It is not raining yet. But the sky is cloudy and you think that it could rain. We use the present simple tense to talk about the possible future condition. We use WILL base verb to talk about the possible future result. The important thing about the first conditional is that there is a real possibility that the condition will happen. Here are some more examples:

IF	Condition	Result
	present simple	WILL base verb
If	it's sunny,	we'll go to the park.
If	you cook the supper	I will wash the dishes.
If	they do not pass their exam	their teacher will be sad.
If	it rains tomorrow	will you stay at home?
If	it rains tomorrow	what will you do?

Sometimes, we use shall, can, or may instead of will, for example: If you are good today, you can watch TV tonight