Good morning, class. Today’s topic is "Idioms and Their Origins". An idiom i

Good morning, class. Today’s topic is "Idioms and Their Origins". An idiom is a phrase or expression with a special meaning. The meaning of an idiom often cannot be understood from the meaning of the individual words in it. In our language, idioms are an important part and they often make our language more colourful. So in today’s lecture, let’s look at the origins of some English idioms. The first idiomatic expression on our list is "Raining cats and dogs". This is an interesting phrase. It is not related to the well-known antipathy between dogs and cats, which is vividly described in the phrase "fight like cat and dog". However, there are several common theories about the origin of the well-known expression, "Raining cats and dogs". One theory is that long ago in England, the roofs on houses were made of hay. You’ve probably heard of thatch-roofed houses, well that’s all they were. Thick straw, piled high, with no wood underneath. Those thatch roofs were the only place for the little animals to get warm. So all the pets in the house; dogs, cats and other small animals, even mice, rats, bugs, all lived in the roof. When it rained it became slippery so sometimes the animals would slip and fall off the roof. Thus the saying, "it’s raining cats and dogs. " Another explanation is that heavy rain would wash dead animals down the streets. In the 18th-century, streets in England were rather filthy and heavy rain would occasionally carry along dead animals and other debris. The animals didn’t fall from the sky, but the sight of dead cats and dogs floating by in storms could well have caused the coining of this colourful phrase. The most popular one comes from Northern European myth in which cats were a symbol for rain and dogs a symbol for wind. Thus, "it’s cats and dogs out there. " is often used to describe a heavy rain storm with strong winds.