There are many ways of putting out a fire.
You may have seen people put out burning cigarettes by stepping on them. Stepping on a burning cigarette shuts off the air and puts out the fire.
Many fires are put out with water. Water cools the material that is burning. It helps smother (闷熄) a fire, too. Some of the water is changed into steam when it strikes the hot fire. The steam shuts off air from the fire and helps put it out.
Some fires cannot be put out with water. They have to be smothered with sand or with chemicals of some kind, such as those used in some fire extinguishers (灭火器). Suppose a tank full of gasoline is on fire. Gasoline is lighter than water. If you poured water into the tank of gasoline, the water would sink to the bottom of the tank. The gasoline would float on top of the water and would probably keep on burning. If you keep on putting water on the fire, the gasoline would flow over the edge of the tank. Then the fire would spread.
What are the major ways of putting out fires as mentioned in the passage
With water, ______.