What makes the digestion of carbohydrates, which paused in the stomach, resume in the duodenum?

The major enzyme which digests carbohydrates is called amylase. This works at a pH of approximately 6.5 to 7. Since the stomach is filled with hydrochloric acid (pH 1 to 3), the amylase enzymes cannot cope with the conditions and so they stop working. (The scientific mumbo-jumbo for this is "they become denatured and their active site deforms") Once the carbohydrates have passed through the stomach, they move into the duodenum where three enzymes are secreted by the walls of the small intestine which allow the food to be broken down further. (The science term for this type of breaking down is "hydrolyzed").