Gas tank

Using natural gas sent through pipelines is a privilege enjoyed by residents of major cities. In many families, gas tank is still the best thing they can access. When the liquefied gas is about to be finished, an experienced housewife would shake the tank and the remaining gas can boil a bottle of water. It is a labor to carry a gas tank weighing some 20 kg upstairs. For a vigilant mother, an effective way of finding out the capabilities and honesty of her future son in-law is to send him on a mission of getting a new gas tank.