We use the second conditional to talk about the things we would do if something very unlikely or impossible happened.
If I won the lottery, I would buy a sports car
If I were the President, I would go to war
Unlike the first conditional and zero conditional, the second conditional uses the past tense and uses ‘would’ instead of ‘will’:
Zero conditional: If water reaches 100C, it boils
1st conditional: If I win the lottery, I will buy a sports car
2nd conditional: If I won the lottery, I would buy a sports car
In essence, using the past tense and ‘would’ helps ‘to distance our language from reality’ (Practical English in Usage, p.234) meaning we can talk about unlikely or unrealistic situations. This is where the two conditions are fundamentally different.
The second conditional uses the condition and then the result.
If I had enough money I’d buy the New York Jets
If there were more people on the planet we might have no space to live
If they finished work early today they could spend more time with their family
Notice that each condition is either unlikely or won’t happen. Also notice that the result could, might or would happen. The second conditional will typically use ‘would’, but this can change to could or might, for example, if the result is more likely or more unlikely to happen.
Using 2nd conditional to ask questions
By using the 2nd conditional, you can ask about unlikely scenarios and what someone would do if they were in the situation.
1). What would you buy if you could buy anything in the world?
What would you do if you could do anything today?
Responses may be rearranged. So for example
1). If I could buy anything in the world, I would/ If I were able to buy anything in the world, I would buy…
2). If I could do anything today, I would/ If I were able to do anything today, I would….
Notice that this means the conditional and result change positions also.
Using 2nd conditional for advice
If I were you, I’d help
I’d go with them to the supermarket if I were you