Conditional sentence consists of 2 parts of the main clause sentences and sentences with if Clause (in case). In English conditional sentences there are 3 types:
I. Future Possible
This is used to denote an action that will be / happen in the future if a condition fulfilled. The possibility of doing that, depending on the condition that met or not. Attitudes of the speaker in this case showed the neutral and still hope that these actions can occur. For this type of sentence structure as follows:
• Main clause _ simple future tense
• If clause_ simple present tense
e.g : If you study hard, you will pass the examination.
If the weather is fine tomorrow, we will go for a picnic.
If I go to England, I will visit Buckingham Palace.
I will Buy a car if I have much money.
He will tell you if he knows the answer.
Unless – If Not
Unless used to replace if not, for negative statements. Note in the sentence below:
e.g. * If you don’t take an umbrella. You will get wet.
– Unless you take an umbrella. You will get wet.
* If you don’t study hard. You won’t pass the examination.
– Unless you study hard. You won’t pass the examination.
* If it doesn’t rain tomorrow. I will go for a swim.
– Unless it rains tomorrow. I will go for a swim.
* No one will come to the door if doesn’t ring the bell.
– No one will come to the door unless he rings the bell.
* We will be late if we don’t leave now.
– We will be late unless we leave now.
II. Present Unreal
This section is used to declare a state of different / opposite of the reality in the present. appropriate sentence structure as follows:
• Main clause _ past future tense
• If clause_ future tense simple
e.g: -) If you studied hard, you would pass the examination.
(You don’t study hard).
-) If I had a car. I would take a trip to bali. (I don’t have a car).
-) If my father knew how to drive. He would buy a car.
(My father doesn’t know to drive).
-) I would eat japanese food if I lived in japan. (I don’t live in japan).
-) He would buy a new house if he had much money.
(He doesn’t have much money).
If the phrase is expressed by to be, then we use for all subjects were. Like this :
e.g: -) If I were the moon, you would be the star.
-) If I were a bird, I would fly all over the world.
-) If he were not busy this time, he would help you.
-) If I were him, I wouldn’t do that.
-) If I were rich, I would make a trip around the world.
III. Past Unreal
Past unreal is used to express a different situation, and contrary to reality in the past. composition of the sentence as follows:
– Main clause _ Past future perfect tense
– If clause _ Past perfect tense.
e.g: -) If he had gone to the concert last night, he would have seen Mary.
(He didn’t go to the concert).
-) If I had seen you yesterday, I would have told you about it.
(I didn’t see you yesterday).
-) If weather had been fine yesterday, we would have gone for swim.
(the weather was bad yesterday).
-) If you had told her the truth, she wouldn’t have been angry.
(You didn’t tell her the truth)
-) If I had received your message, I would have come at once.
(I didn’t receive your message).