Suck the air out of a bottle and your tongue and lips will stick to the mouth of the bottle, because you have created an imbalance (a vacuum), which now must be filled.

• 如果你用嘴吸出瓶子里面的空气，那么你的舌头和嘴唇就紧紧粘在瓶口上，因为我们制造了不平衡（真空），所以要填补这种不平衡。