potatoes and wax gourd need to be peeled, and eggplant also needs to be peeled in some dishes (such as roasted eggplant, fresh potatoes, etc.); When frying these dishes alone, eggplant, potato and wax gourd can be added with vinegar and soy sauce according to personal taste, and it is best not to add soy sauce vinegar for tomatoes to maintain their original flavor. In addition, some practices can only add soy sauce or vinegar, such as: stir-fried potato shreds can only add vinegar, sauce eggplant, grilled eggplant can add soy sauce without vinegar.