Type I
Conditional sentences type I express possibilities. They refer either to the present or the future. They state conditions, under which certain things will come true.
To form a conditional sentence type I, you need an if-clause starting with "if" and a main clause. The main clause could either be in the will-future, or a clause with a modal verb and an infinitive, or an imperative.
It looks like this:
If I arrive in time, …
… I willcome and help you.
… I could talk to him personally.
… please wait for me at the door.
The most common version of the conditional sentence type I is the one with "will". Here are some more examples:
- If the weather is good tomorrow, we will go swimming.
- If you are hungry, we will stop by a restaurant.
- If the children behave well, they will be allowed to visit their friends.
- If you drive to fast, you will cause an accident.
Try that out by doing the following exercise! Always use the will-future in the main clauses!
It goes like this: he – to find out – to be very happy 
If he finds out, he will be very happy.
If he finds out, he will be very happy.In the next exercise, you will have to use all three possible ways to form the main clause. It is a bit more difficult.