Frying vegetables with vinegar will cause great loss of nutrition (1). Chlorophyll in vegetables is very unstable when heated under acidic conditions. Magnesium ions in its molecule can be replaced by oxygen ions in acid, resulting in a dim pheophytin from olive, and its nutritional value is greatly reduced. (2) Precautions: When cooking green vegetables, stir fry quickly under neutral conditions, which can not only keep the vegetables bright green, but also reduce the loss of nutrients.