Conditional sentences

srcs: 

1. https://www.youtube.com/watch?v=h-Np7dmvw0U&t=516s
2. https://www.youtube.com/watch?v=HwKARnadyE0
3. https://www.youtube.com/watch?v=FH3ThwR99LM

There are 4 type of conditions:

1. Condition 0: 
1. Second clause(then clause) is 100% true.
2. Habits, facts or truths.
3. If + Present Simple ---> Present Simple
4. What actually happens.
5. If I get sick, I go to the doctor.

Eg: 

1. If you put ice in your drink, it melts.

Note: In condition 0, ‘when’ can also be used instead of ‘if’

When I get sick, I go to the doctor.

(Only in condition 0, remember)

2. Condition 1: 
1. Second clause(then clause) is very likely to be true but not 100%.
2. Present or future situation of high probability.
3. If + Present simple ---> Future simple
4. Possible, likely future outcomes.
5. What could happen.
6. If I get sick, I will go to the doctor.
7. If + were
1. If I were a lawyer, I wouldn’t take on this case.
2. If I were you, I would do it.
1. I would do it if I were you.

Eg. 

1. If father is at home, I will come.
2. If you come, I’ll also come.
3. If he becomes the Prime Minister, the country will grow.
4. If I had any time, I would tidy up my office.(I don’t have any time).
5. If I were a lawyer, I wouldn’t take on this case.

3. Condition 2: 
1. If + Past simple ---> Would + V1
2. When we want to imagine that present situation is different. (Condition, not outcome. As the outcome could still be improved if the situation had been different)
3. What we wish would happen.
4. If I got sick, I would go to the doctor. (Just an imagination, as I’m hale and hearty now.)
5. If I had(have had) more money, I would buy this car. (As currently, I do not have enough money to buy this car).
6. If I went, I would meet him.
7. If I were the PM, I would show you my capability.
8. If he came, he would scold you.

More cases:

1. Hypothesis. When we want to imagine that present situation is different.
1. If I had more money, I would buy this car.
2. If he came, he would scold you.(He did not come)
3. If I went, I would meet him. ( I did not go)
2. Present / Future situation of low probability.
1. If I got sick, I would go to the doctor. (I don’t feel I’m going to get sick. But If I got sick, I would go the doctor)

4. Condition 3: 
1. When we want to imagine the past situation in a different way. 
2. Pass situation with zero probability. Can’t be changed now
3. If + Past perfect ---> Would have + V3
4. What might have happened.
5. Third conditional sentences are used to explain that present circumstances would be different if something different had happened in the past.
6. If you had told me you needed a ride, I would have left earlier
7. If I had been sick, I would have gone to the doctor.
8. Condition 3 and condition 2 both  deals with past if claused, the difference is in the consequences clause. In condition 2, the work is still can be done if the ‘if’ clause turned true, whereas in the condition 3, the work can’t be done, even if the condition in ‘if’ clause turned true now.(Regardless of the probability, very less in both cases.)

Eg.

1. If we had locked at the weather report, we would have stayed at home.
2. If I had known you were visiting, I would had made time to see you.
3. (I didn’t see her yesterday)
1. If I had seen her yesterday, I would have spoken to her.
2. OR Had I seen her yesterday, I would have spoken to her.
3. OR I would have spoken to her had I seen her yesterday.
4. (They weren’t late last night)
1. If they had been late, I wouldn’t have let them in.
2. I wouldn’t have let them in If they had been late.
5. (I was not there)
1. If I had been there, I would have met him.
6. (I’m not a doctor)
1. If I studied, I would have become a doctor.
7. (I’m not the PM)
1. Had I been the PM, I would have shown you my capabilities.

Notes:

1. Condition 1 VS Condition 2
1. Eg. 1
1. Condition 1: I often see her
1. If I see her tomorrow, I will speak to her.
2. Condition 2: I don’t often see here
1. If I saw her tomorrow, I would speak to her.
2. Eg. 2
1. Condition 1: I think there will be a change
1. If anything changes, I will let you know.
2. Condition 2: I don;t think there will be a change
1. If anything changes, I would let you know.
2. When If clause is the second clause, omit the comma.
1. Had I seen her, I would have spoken to her.(I didn’t see her yesterday)
2. I would have spoken to her If I had seen her yesterday.(No comma required)
1. OR: I would have spoken to her had I seen her yesterday.
3. Special cases
1. Use of ‘would’ for politeness
1. If you follow me please, I’ll show you your room.
1. If you’d(would) follow me please, I’ll show you your room.
1. Note: ‘would’ is there but this is in present simple so still condition 1
2. Imperatives & requests in Condition1.
1. If you see John, please give him this book.
2. Could you give John this book please if you see him?
3. If you aren’t busy, may I see you for a minute?
3. Use of ‘may’(condition 1), ‘might’(condition 1,2 and 3) and ‘could’(condition 1,2 and 3). These can be used in ‘consequence’ clause to reduce the certainty of the action of that clause.
1. Eg. Condition1:
1. If I see her tomorrow, I will speak to her. (No doubt that I will speak to here If see her tomorrow)
2. If I see here tomorrow, I may/might/could talk to her.(Doubtful that I talk to here, even when I see her)
2. Eg. Condition 2:
1. If they were late again, I would not let them in.(Getting late is less probable but will not let them is certain if first condition met)
2. If they were late again, I might not let them in.(Doubtful, getting late is less probable by definition of condition2, but not them also gets less probable by adding ‘might’)
3. Eg. Condition 3:
1. If I had some time, I would have tidied up my office.
2. If I had some time, I might/could have tidies up my office.(Does not have time, but sill If I had, tidies up changes are reduced by adding ‘might/could’.
4. Use of the Simple Future in the If-Clause a. when the action in the if-clause will take place after the action in the main clause. For example, consider the following sentence Eg: If aspirin will ease my headache, I will take a couple tonight The action in the if-clause is the aspirin easing the headache, which will take place only after the speaker takes them later that night.

1. Avoid using ‘should’ instead of ‘will’ or ‘would’ in a conditional sentences.
1. If I knew his name, I would(“should” is wrong here) say hello to him.
2. Avoid using ‘when’ in place of ‘if’ in conditions 1,2 and 3. Only allowed for condition 0.
1. Condition 1:
1. When I see her, I will speak to her.(Sentence is correct but it means that I certainly see her)
2. Condition 2: 
1. When it were a little warmer, I would go for a swim.
1. Wrong sentence.
3. Condition 3:
1. When I hadn’t had so much coffee, I would have slept better.
1. One again, wrong sentence.
3. Using ‘will’ or ‘would’ twice
1. Condition 1:
1. Wrong: If you will come back tomorrow, I will give it to you then.
2. Corrented:  If you come back tomorrow, I will give it to you then.
2. Condition 2: 
1. Wrong: You would miss the bus if you wouldn’t leave now.
2. Corrented:  You would miss the bus if you didn’t leave now.
3. Condition 3:
1. Wrong: No one would have noticed if you wouldn’t have said anything.
2. Corrented: No one would have noticed if you hadn’t said anything.
4. Mixing up one condition with another.
1. Condition 1 and condition 2
1. Wrong: How much would it be if I pay cash?
1. Corrected in condition 1: How much will it be if I pay cash?
2. Corrected in condition 1: How much would it be if I paid cash?
2. Condition 2 and condition 3
1. Wrong: If you come earlier, we would have had more time.
1. Corrected in Condition 2: If you came earlier, we would have more time.
2. Corrected in Condition 3: If you had come earlier, we would have had more time.

Were to more examples:

If I were to be sick, I would miss another day of work.

If she were to be late again, she would have to have a conference with the manager.

If the rent were to have been a penny more, they would not have been able to pay it.