Cats and dogs are the most popular pets.Do you keep a cat ,or a dog,too?

　　"It's raining cats and dogs"is a much used idiom.How come it means "it is raining very heaveily"?That has somethig to do with a western myth.According to the myth,both the cat and the dog are sevants of the god of storm.

　　You may laugh at the expression"enough to make a cat laugh",It means "very funny".When a lumsy fat boy slips on a banana skin ,it is enough to make a cat laugh.