My English blog

In medieval markets pigs were commonly sold and traded. In an effort to keep the piglets secure, they were sold in tightly tied bags which the new owner was not to open until he or she was in a safe place at home. Often times, shady traders would put a cat instead of a piglet in the bag. Thus, the buyer wouldn't know the secret until at home. Letting the cat out of the bag also let the secret out

 Let the Cat Out of the Bag  

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