You know that pearls grow inside oysters(牡蛎), but would you ever think to look for diamonds inside an ostrich(鸵鸟)? Well, a hunter once shot  an ostrich and discovered, to his great surprise, that the big bird had swallowed a bunch of diamonds. How could such a strange thing happen?Like many other birds, the ostrich swallows small stones that stay inside its “gizzard”. The gizzard is a bird’s second stomach. It is where the food is ground up. The small stones help to grind up the food so it can be digested. The small stones do the chewing because birds don’t have teeth. In that case of the ostrich with the diamonds, the bird simply had expensive taste in rocks. It used the diamonds to digest its dinner. Diamonds and stones aren’t all that an ostrich will swallow. If there are no stones around, it will eat just about anything. Sadly for ostriches in zoos, this can be a fatal h  abit. The tendency to swallow anything it sees has caused the death of many an ostrich. Cruel or careless people often throw things into the bird’s living space. They throw keys, coins, and even large objects such as horseshoes. The ostrich swallows them without hesitation. Coins can be the worst. Inside the ostrich they wear down to a razor-sharp edge. They will cut open the bird’s gizzard from the inside. When one young zoo ostrich died, 484 coins weighing more than eight pounds were found in its gizzard.小题1: Which of the following best expresses the main idea of the passage?
The ostrich is not smart enough to ______.
The sentence “the small stones do the chewing” makes rocks seem as though they were ______.
he word “fatal” in the third paragraph is another word for “______”.
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e