This is just one theme introduced in Act 1.3. Numerous other themes are revealed: evil, ambition, the unnatural, the grotesque, and others. Ironically, when Banquo warns Macbeth that the witches may be tricking him in order to later bring him harm, he pretty much summarizes the plot of the rest of the play.
"He exercised while I watch television." because the tenses of the verbs don't match--"exercised" is past tense and "watch" is present.
Answer:
a story, poem, or picture that can be interpreted to reveal a hidden meaning, typically a moral or political one. hope this helps
