A. The professor often kept his students sharp by using a textbook alarm.

B. The author left the two-hour period not only wide awake, but a little smarter.

C. The author was attracted by the professor's great wisdom and enthusiasm.

D. Though the author was frightened awake, he was not clear-headed in the class.

Scientists have always been interested in the high level of organization in ant societies. American researchers have watched ants build life-saving rafts(筏子) to keep afloat during floods. They also have documented how ant colonies choose their next queen - the female whose job is to produce eggs rather than seek food for others.

New technology is helping to improve researchers' understanding of the insects. But there is still a lot to be learned. Fire ants living in Brazilian forests are perfectly at home in an environment where flooding is common. To save themselves, the insects connect their legs together and create floating rafts. Some ant rafts can be up to 20 centimeters wide.

David Hu, who is a mechanical engineer with the Georgia Institute of Technology, also known as Georgia Tech, says, "If you have 100 ants, which means 600 legs, 99 percent of those legs will be connected to a neighbor. So they're very, very good at maintaining this network."

David Hu and other Georgia Tech researchers want to study ants and the secret of their engineering. They freeze ant rafts and then look at them with the help of computed technology, or CT, images. The pictures show that larger ants serve in central positions to which smaller ants hold. The larger ants form pockets of air that keep the insects afloat.

Scientists say small robots or materials that can change shape could be programmed in a similar way, working towards a shared goal.

Researchers at North Carolina State University are also studying ants. They examined how Indian jumping ants choose the leader of the colony when they lose their top female or queen.

5. The duty of the queen ants is to_____.

A. seek food B. keep organized C. lay eggs D. keep guard

6. The author takes fire ants as an example to tell us _____.

A. how ants seek food perfectly B. How ants save themselves from floods

C. how ants communicate D. How ants connect their legs together

7. Which of the following is true according to the passage?

A. Ants know the way to form a harmonious society.

B. The Georgia Tech researchers first discovered Indian jumping ants.

C. All the worker ants in the colony are physically larger.

D. Small and shaped-changeable things might work just like ants do.

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