3 . Scientists say they’ve witnessed a never-before-seen type of reproduction in organic robots created in the lab using frog cells.

The discovery involves a xenobot—a simple, “programmable” organism that is created by bringing stem cells together in a lab. “You can think about this like using the different cells as building blocks like you would build with LEGO,” Douglas Blackiston, a co-author of the study says. The xenobots are made of cells taken from an African frog. The cells aren’t genetically changed at all, but simply combined in different arrangements to produce the xenobots, says Blackiston. What the xenobots did—self-replication—is new in living organisms, says Michael Levin, a professor of biology at Tufts. It does happen at the molecular (分子的) level, but “we are not aware of any organism that reproduces in this way,” he says.

Xenobots are collections of living cells and have no brain or digestive system. But in a real sense they can be programmed—to corral other cells, as in this study, or eventually to do other things. That’s why the researchers think of them as tiny organic robots. “The distinction between a robot and an organism is not nearly as sharp as... we used to think it was,” Levin says. “These creatures, they have properties of both.”

The xenobots fuel themselves by using tiny hair-like structures. They have a tendency to spin, which “turns out to be pretty good for collecting piles of things,” such as other cells, Blackiston says. So the team used an artificial intelligence-driven computer simulation (模拟图像) to see how they might control the xenobots into shapes that would be even better at piling things up. The researchers hope that one day these xenobots could be programmed to perform useful functions such as finding cancer cells in the human body or trapping harmful microplastics in the ocean.

But that concerns some scientists. Nita Farahany is a professor who studies the ethics involved in new technologies and was not part of the xenobot research. “Any time we try to improve life by means of tech... we should recognize its potential to go really poor,” she said.

1. What do we know about the study according to the first two paragraphs?

A．The research methods involve LEGO building.

B．The cells are genetically changed in the study.

C．The self-reproduction takes place in organic robots.

D．The xenobots are made of cells taken from plants.

2. What could xenobots be used for in the future?

A．Killing cancer cells in the human body.

B．Gathering harmful microplastics in the sea.

C．Purifying sea water to expand water resources.

D．Replicating damaged organ to avoid transplanting organs.

3. What is Nita Farahany’s attitude towards the discovery?

A．Worried.	B．Ambiguous.
C．Favorable.	D．Indifferent.

4. Where is this passage most likely from?

A．A book review.	B．A guidebook.
C．A science fiction.	D．A scientific journal.

4 . The Metropolitan Museum of Art

1000 Fifth Avenue New York, NY 10028

211-535-7710 www.metmuseu.org

Entrances

Fifth Avenue at 82nd Street

Hours

Open 7 days a week

Sunday-Thursday 10:00-17:30

Friday and Saturday 10:00-21:00

Closed Thanksgiving Day, December 25, January 1, and the first Monday in May.

Admission

$25.00 for adults, a discount of 30% for students above 12, includes the Main Building and the Cloisters (回廊) on the same day; free for children under 12.

Free with Admission

All special exhibitions, as well as films, lectures, guided tours, concerts, gallery talks, and family/ children’s programs are free with admission. Ask about today’s activities at the Great Hall Information Desk.

The Cloisters Museum and Gardens

The Cloisters Museum and Gardens is a branch of The Metropolitan Museum of Art devoted to the art and architecture of Europe in the Middle Ages. The extensive collection consists of masterworks in sculpture, colored glass, and precious objects from Europe dating from about the 9th to the 15th century.

Hours: Open 7 days a week.

March-October 10:00-17:15

November-February 10:00-16:45

Closed Thanksgiving Day, December 25, and January 1.

1. How much may they pay if a 13-year-old girl and her parents visit The Metropolitan Museum of Art?

A．$32.5.

B．$50.

C．$57.5.

D．$67.5.

2. The attraction of the Cloisters Museum and Gardens lies in the fact that ______.

A．it opens all the year round

B．it has a modern European-style garden

C．its collections date from the Middle Ages

D．it sells excellent European glass collections

3. When can visitors go to neither of the two museums?

A．On Sundays.	B．On May Day.
C．On January 1.	D．From Thanksgiving Day to Christmas.