A bag is useful and the word "bag" is useful, too. Here is an interesting phrase, "to let the cat out of the bag". In meaning it is the same as "to tell the secret". And there is an old interesting story about it.
Long ago, when farmers wanted to sell chickens at the market, they would usually just throw the chickens in cloth (布) bags. But cats were cheaper than chickens at that time, so many farmers would put cats into the cloth bags but not chickens. One day, a woman asked a man for a chicken. The man gave her a cloth bag in which there was a cat.   When the man opened the cloth bag, a big black cat ran out. Not a chicken! The man's secret was out and everyone knew it.
Now when we say someone gives away a secret, we say "He lets the cat out of the bag". And that is the story where the interesting phrase came from.
The underlined word "it" in the passage refers to (指的是) _______.

A．the useful bag B．the phrase C．the cat D．the chicken

A．tell the secret B．sell the cats C．get more money D．keep the cats quiet

A．The woman was angry to see a cat. B．The man put a cat in the bag. C．The man asked her to see the chicken. D．The woman wanted to see the chicken.

A．the woman was smart B．how farmers sold their cats C．the phrase is useful D．where the phrase came from