A、Two. B、Twenty-six. C、Twenty-eight. D、Thirty. C细节题。文中明确提到在抢劫案发生之前，Baby had only a 28一wordvocabulary(鹦鹉只有28个单词的词汇量)，故答案为C)。

For centuries, parrots have been prized pets because of their strange talent for imitating human speech. They are able to hear vocal ranges, memorise the tones, and then repeat what they have heard.[22]Often this skill is used to entertain people. But recently, an Amazon parrot, named Baby, was able to put this ability to work by helping police break up a gang of burglars responsible for over $50,000 in property theft.
    Baby helped the police to identify the gang of thieves. A recent robbery victim reported to the Baytown, Texas police that her parrot, Baby, started acting strangely and saying new phrases after the robbery.
     [24]Before the robbery, Baby had only a 28-word vocabulary; afterwards, the bird started saying the additional phrases "Come back, Robert!" and "Come here, Ronnie!".
    The police detectives were delighted. Although one man had already been arrested, Ronnie and Robert were the names of their two top suspects who were believed to have aided the first man. Under questioning, this suspect explained what had happened. When the robbers, entered the house, they heard Baby talking and thought that someone was home. Ronnie and Robert began running away, while the third man yelled for them to come back. Baby remembered this incident and recorded their voices in her memory.
22. What is a parrot’s skill often used to do when imitating human speech?
23. How did Baby help the police?
24. How many words was Baby able to say before the robbery?
25. Which of the following would be the best title for this passage?