What are conditionals in English grammar? Sometimes we call them 'if clauses'. They describe the result of something that might happen (in the present or future) or might have happened but didn't (in the past) . They are made using different English verb tenses.
We can make a zero conditional sentence with two present simple verbs (one in the 'if clause' and one in the 'main clause'):
The 'if' in this conditional can usually be replaced by 'when' without changing the meaning.
The first conditional has the present simple after 'if', then the future simple in the other clause:
The first conditional describes a particular situation, whereas the zero conditional describes what happens in general.
First vs. Second Conditional:
The first conditional describes things that I think are likely to happen in the future, whereas the second conditional talks about things that I don't think will really happen. It's subjective; it depends on my point of view.
For example (first conditional): If she studies harder, she'll pass the exam (I think it's possible she will study harder and so she'll pass)
But (second conditional): If she studied harder, she would pass the exam (I think that she won't study harder, or it's very unlikely, and so she won't pass)
First, we can use it to talk about things in the future that are probably not going to be true. Maybe I'm imagining some dream for example.
We make the third conditional by using the past perfect after 'if' and then 'would have' and the past participle in the second part of the sentence:
if + past perfect, ...would + have + past participle
It talks about the past. It's used to describe a situation that didn't happen, and to imagine the result of this situation.