Mixing tenses

Question

When is mixing past and present tenses permitted?

For example, would "Es posible que se muriera ayer." be grammatically valid?

Answer 1

Your example is totally valid. About your other question, i think that it is not easy to delimit it with a rule. Maybe you have to learn it verb by verb. The kind of example that you used can be used to undestand it: The action was done in the past, but you are "valuing" it now.

No es cierto que España no mereciera ganar el mundial de futbol.

The action was five or six years ago, but you are valuing it now.

This is the only case i can remember now.

Thanks mate for your answer, very kind of you . - ray76, May 7, 2015