LPG is a fuel. The letters mean liquefied petroleum gas: gas that comes from oil, kept as a liquid in a strong bottle so you can carry it and store it.

LPG LPG is是 a fuel一種燃料。 The letters mean這幾個字母的意思是 liquefied petroleum gas「液化石油氣」: gas that comes from oil從石油來的氣體, kept as a liquid in a strong bottle被裝成液態放在堅固的鋼瓶裡 so you can carry it and store it這樣才能搬運和儲存。

When you open the tap, it turns back into gas and you burn it for heat or power — a stove, a water heater, a room heater, or, in some places, a car or a bus.

When you open the tap打開開關的時候, it turns back into gas它會變回氣體 and you burn it for heat or power你就拿它來燒，取得熱或動力 — a stove瓦斯爐, a water heater熱水器, a room heater暖爐, or, in some places有些地方甚至 a car or a bus是汽車或公車。

It is mostly propane and butane, not the same stuff as the gas that comes through pipes under the street (that is usually natural gas, mostly methane).

It is mostly propane and butane它主要是丙烷和丁烷, not the same stuff as the gas that comes through pipes under the street跟走管線從街道底下來的瓦斯不是同一種東西 (that is usually natural gas, mostly methane)（那種通常是天然氣，主要是甲烷）。

A smell is added on purpose, because the real gas has almost no smell and you need to notice a leak. It is handy where there are no pipes; the bottle is under pressure, so people treat it with care.

A smell is added on purpose特意加了臭味, because the real gas has almost no smell and you need to notice a leak因為真正的氣體幾乎沒有味道，你需要能察覺到漏氣。 It is handy where there are no pipes在沒有管線的地方它很方便; the bottle is under pressure因為鋼瓶是加壓的, so people treat it with care人們會小心對待它。

Though actually, in everyday talk people often just say “gas” and do not bother with the letters.

Though actually不過實際上, in everyday talk people often just say日常說話人們常常就直接說 “gas”「瓦斯」 and do not bother with the letters懶得講那幾個字母。