Dr. Irene Pepperberg, a scientist at the University of Arizona，has worked with Alex for nineteen years. Teaching Alex to speak and understand wasn’t easy at first．He had to learn one word at a time. Irene and an assistant(助手)would teach Alex by showing him what a word meant．Irene would hold up an object, saying “What’s this?” Her assistant would give the word—“candy”，for example—while Alex watched .Irene would praise(表揚(yáng))her assistant, then ask Alex the name for the object．When he got it right，Irene would praise him and give him the object to play with as a reward．It took Alex many weeks to1earn his first word．After that，each new word became easier and easier for him．

Why did Irene spend so much time getting a parrot to talk? Scientists like Irene are interested in discovering how intelligent(聰明)animals are and hew their brains(大腦)work. But studying animal intelligence has always been difficult, partly because animals haven’t been able to communicate(交流)clearly with humans．Teaching Alex to speak words that he understands has let Irene talk to him directly．She can ask him questions，and he can answer them in English．In this way，Irene is finding out what kinds of things Alex’s brain can do．She has found that parrots are much smarter than scientists used to think.

1．According to the passage，how is Alex remarkable(不尋常的)?

  A．He can use the English language to answer questions．

  B．He uses words in English instead of bird calls to call other birds．

  C．He can copy the pronunciations of more than 100 English words．

  D．A1ex has a brain that is much bigger than those of other parrots.

2．How did Dr. Pepperberg teach Alex to speak with understanding?

  A．She said the same word all day long so that Alex could repeat it.

  B．She taught Alex a special sign language．

  C．She gave Alex rewards if he would say what she said．

  D．She gave Alex a candy every time he answered correctly．

3．Why did Dr. Pepperberg teach Alex to speak with understanding?

  A．She wanted to prove it could be done．

  B．She wanted to provide a model for people who want talking birds．

  C．She wanted to find out how many words parrots could remember.

  D．She wanted to find out what kinds of things his brain could do.

4．According to the passage，Alex has proved that       ．

  A．birds are not the only animals that can learn a language

  B．parrots are much cleverer than scientists used to think

  C．birds age just as intelligent as humans

  D．teaching parrots to speak a human language isn’t very difficult