Final answer:
Dwight can tell when an angel is lying by observing people's reactions and expressions when they are in front of the angel.
Step-by-step explanation:
Dwight can tell when an angel is lying by observing the reactions and expressions of people who are in front of the angel. For example, if the figure is kneeling and clutching the sides of their head with a terrified expression, it suggests that the angel's statement is shocking and unbelievable. This can serve as a clue for Dwight to recognize when an angel might be lying.