Verb tenses are syntactically and morphologically encoded categories that express the temporal location of an event or state, often combining with aspect to indicate its duration, completion, or recurrence. Moods, conversely, are grammatical categories that express the speaker's attitude toward the proposition's factuality, possibility, necessity, or desirability.
The English tense-aspect system fundamentally operates on a bi-dimensional grid: Tense (past, present, future) and Aspect (simple, progressive, perfect, perfect progressive).