Amazed zoo visitors watch as an orangutan(猩猩) named Bonnie swings along cables way above their heads. She’s not making a great ape escape; she’s taking a “highway” to higher learning.

Bonnie is traveling on the Orangutan Transit System, called the O-Line, at the National Zoo in Washington, D.C. The O-Line stretches from the Great Ape House, where Bonnie lives, to an exhibit called Think Tank. There she and other orangutans participate in a study trying to answer the questions: Do animals think?  If so,  how?

    Think Tank scientists look for clues that an animal is thinking. A baby orangutan following its mother is probably not thinking. But an orangutan using a stick to reach honey in a beehive probably is thinking. It’s figuring out how to obtain a sweet treat.

    To learn more about what the orangutans are thinking, Think Tank scientists are teaching orangutans a language of symbols. The apes don’t actually speak. They point to the symbols to show their thoughts.

    Each symbol stands for a word. Different categories of the symbols have their own shapes. Food symbols, for example, are rectangles(矩形); object symbols are circles; and verbs are diamonds.

    Computers help the orangutans learn the symbolic language. After the apes are shown an apple, for example, their task is to touch the apple symbol on a computer screen. They can do so. All six orangutans have learned a few symbols, but only Azy and Indah have learned eight symbols and can use the computer.

    Azy and Indah choose to live at Think Tank. The others commute(往返) from the Great Ape House on the O-Line. All attend Think Tank sessions, though none are made to do so. “They’re eager to learn”, one of the scientists says. “They never turn me down!”

What is the main idea of the passage?

Scientists are doing research on whether animals can think and how they think.

Biologists have found that orangutans are more intelligent than other animals.

Orangutans at the National Zoo can be taught to communicate with humans easily.

Animals are being taught by scientists to speak to one another at the National Zoo.

     The Orangutan Transit System refers to _____.

a way that can teach animals to learn things and communicate quickly

a place for various animals in the National Zoo to participate in the study

a walkway for the orangutans to travel to different sections of the zoo

a line for the orangutans to travel between the Great Ape House and the Think Tank

     According to the passage, scientists use a system of symbols to help _____.

find out which orangutan can learn the symbolic language fast

attract all the orangutans to live together at Think Tank

communicate with the orangutans and understand them better

understand whether animals can learn a language and express themselves by using it

     It can be inferred from the passage that _____.

a baby orangutan has his own intention though following his mother

many animals in the wild can learn symbolic languages to express their thoughts

the cleverer the animals are, the more knowledge they would like to learn

orangutans can form mental images in their minds when they see objects