Plug all possible vents in the bottle, leaving only one straw, and the straw head should be immersed in water. Blow into it. Because the volume is limited, the pressure of a gas will naturally increase, just like breathing. If the pressure inside is greater than the pressure outside, the gas will run out. Similarly, when gas wants to escape, the only channel is the other end of the straw, and because the other end of the straw is in water, water will naturally come up.