Most of my students assume that past tenses are only used to talk about past events. This seems logical, after all. Unfortunately it isn't true. We can use past tenses to talk about the past, present and future. Here are some of the main ways we use past tenses:
1. To talk about the past
I went to Ticino at the weekend. It rained every day but even so, I still had a good time.
The Eiffel Tower was completed in 1889.
2. To talk about hypothetical (imaginary) situations in the present or future
If I won the lottery, I would buy a grand piano.
Your mum would be really happy if you helped her more often.
3. To be polite
Would you like a cup of tea?
Could I have a biscuit please.
Using 'past tenses' to be polite doesn't seem to cause my students much difficulty whereas conditional 2 (the second example) seems to be more problematic. Perhaps this is because students learn polite expressions as 'chunks' and don't realise that they are using past tenses. Only a limited number of verbs are used in polite expressions (could, would, should and so on), so this makes these phrases relatively easy to learn.
With conditional two, however, the situation is different. We can use a huge range of verbs in the 'if clause' and need to put this verb into its past form. It might seem counter-intuitive to do this but it's the way that English works! Using a past form creates an idea of distance and shows that the thing we are talking about is not real but hypothetical.
Click here to read Tip #1