Learn Spanish (Latin America): Él mintió, pero la escalera es mejor que el ascensor. - He lied, but the stairs are better than the elevator.

The verb is mentir (to lie). In the preterite (past) tense, -ir verbs that have a stem change in the present also change in the past, but only in the third person (he, she, it, they, you formal). The e in the stem changes to i, making it mintió instead of "mentió".

Why is la escalera singular when the English translation says "the stairs"?

In Spanish, la escalera often refers to a staircase as a single unit. While you can say las escaleras, using the singular is a very natural way to say "the stairs" when comparing them to another single object like el ascensor (the elevator).

I see mejor que means "better than". Would mejor change if we used a plural noun?

Yes! Even though mejor doesn't end in -o or -a, it is still an adjective and must match the number of the noun. Because la escalera is singular, we use mejor. If the subject were plural, it would become mejores que.

Why do we use es instead of está to say the stairs are better?

We use es (from the verb ser) because being "better" is being stated as a permanent characteristic or a general fact about the stairs in this context, rather than a temporary state or condition.