People can often smell pleasant flowers in the park because the molecules that make up flowers are constantly moving and contact with human olfactory cells to smell the fragrance; Liquefied petroleum gas is stored in a steel cylinder under pressure, and the reason why the volume becomes smaller is that the spacing between molecules becomes smaller, so it shows that there is spacing between molecules; Kobayashi only smells the fragrance and can't see the food clearly because he wears glasses, and the water vapor condenses into water droplets and adheres to the glasses, forming a layer of water mist. Because molecules are in constant motion, the molecules that make up the substance can still contact with human olfactory cells and smell the smell. Because air flows, water molecules move faster, and the water of fresh grapes evaporates faster.
So the answer is: molecules are constantly moving; There are gaps between molecules; Water vapor condenses into water droplets and adheres to glasses; Ventilation makes the air flow.