(1) Metal materials are hard and firm, while inorganic nonmetallic materials such as ceramics and glass are hard and fragile. Therefore, tableware made of metal materials with good thermal conductivity and not easy to break should be carried;

(2) The external flame is in full contact with air, and the temperature is the highest when burning. Therefore, when the picnic pot is heated, it should be adjusted to a suitable height and heated by external flame;

(3) The combustion is not prosperous, and a large amount of smoke is produced, indicating that combustible materials cannot fully contact with oxygen, but they are not completely burned; The condition of full combustion of combustible materials is full contact with oxygen;

(4) According to the analysis of the combustion situation, it can be put out by evacuating combustible materials or directly using water to put out the fire.

So, the answer is: (1) a; (2)C； (3) Combustible is in full contact with air (or oxygen); (4) doused with water or covered with soil.