"It's hot outside in the summer, and it's cold inside in the winter."

Riddle: Fireplace

Explanation:

The fireplace burns red, so it corresponds to "serve diligently with a red heart", and the fireplace is used for heating, so it is in line with "treating people with warmth", the hot weather outside in the scorching summer, the cold weather in the house for winter means the fireplace will be useful in winter. The answer is "fireplace", which means that the fireplace will be useful in winter.

A stove is a furnace used for heating and cooking. Stoves that require fuel to be pressurized often have a pump mechanism that pumps air into the fuel bottle to increase the pressure in the bottle, which in turn feeds the fuel into the burner. Multi-purpose stoves can even be used with a variety of fuels, such as gasoline, kerosene, and stain remover. If you choose gasoline as a fuel, it's best to use one with a low octane rating, and unleaded gasoline is even better.

Expanded Information

Traditional stoves use wood and coal combustion for heating. Modern oven is multi-functional, using respectively electric heat or natural gas, the oven is divided into single, double and triple layer type, each layer is independently controlled, can be used at the same time, but also a single layer of single baking oven is divided into single, double and triple layer type, each layer is independently controlled, and generally have automatic thermostat system.

Western oven is a common equipment in the traditional family kitchen, generally horizontal. In the Middle Kingdom of China, they were traditionally used in the restaurant industry rather than in the home, and were mostly vertical. Ancient Chinese ovens were not common, probably due to a lack of fuel.