Difference between past present and future is an example of ?

The difference is that the past is something that happened previously for example Maria singing, present is what is happening at this moment for example Juan is eating and the future is something that will happen after, for example, Lucy will play.

They are verb tenses

lincoln presided over the union victory in the american civil war, which dominated his presidency. a former whig, lincoln ran on a political platform opposed to the expansion of slavery in the territories. his election served as the immediate impetus for the outbreak of the american civil war.