1. ZERO conditional
1.1. Structure
1.1.1. If+ Present Simple ....Present Simple
1.2. Uses
1.2.1. When we want to talk about facts or things that are generally true.
1.3. Examples
1.3.1. If you freeze water, it turns to ice
2. 1º Conditional
2.1. Structure
2.1.1. If+persent simple, subject+will/won't+bare form
2.2. Uses
2.2.1. We use it for possibilities
2.2.1.1. Present:If I have money, I will a mobile phone.
2.2.1.2. Future:If I finally decide to go to the shoe shop, I will buy shoes.
2.3. Examples
2.3.1. If I buy a chair, I will put it in my room
3. 2nd conditional
3.1. Structure
3.1.1. if+past simple, past conditional
3.2. Uses
3.2.1. Imaginary situations in the present or the future
3.3. examples
3.3.1. If I won the lottery, I would buy a ferrari. If I were the president, would increase the minimum salary of a worker
4. Structure
4.1. Had (not) + past participle (-ed/3rd column).
4.1.1. I had fallen asleep.
4.1.2. I hadn't had the chance.
4.1.3. Had you spoken to Katy before she left?
5. Contrast with past simple
5.1. By the time I returned home, he had already left.
5.2. Did the students go home after they had visited the library?
5.3. He began to run after he hadn't seen the cat.
6. Uses
6.1. To talk about time up to up to a certain point in the past.
6.1.1. We'd finished all the water before we were half way up the mountain.