D
In the story of the Crow and the Pitcher from Aesop’s Fables, a thirsty crow drops stones into a narrow jar to raise the low level of water inside so he can take a drink.
Now scientists have evidence to back up that story. Crows actually do understand how to make water displacement(排水量) work to their advantage, experiments show. The results suggest that the birds are, at least in some aspects, as smart as firstgraders.
Researchers, led by Sarah Jelbert at the University of Cambridge, presented six crows with tubes containing water. Inside the tubes, a worm or a piece of meat on a piece of wood was floating, just out of reach of the crow. In front of the tubes, the researchers arranged several rubber erasers that would sink, and some plastic objects that would float. The crows found out that they could drop the erasers into the tubes in order to raise the water level and get their snack.
However, the birds handled awkwardly in experiments in which they could choose to drop objects in either a wide tube or a narrow one to get a snack, the researchers said. Dropping objects into a narrow tube would lift the water level by a greater amount and put the treat within reach after just two drops; while it took around seven drops to raise the snack to the same level in the wide tube. The crows obviously didn’t realize this, and most of them went for the wide tube first.
Previous studies showed that chimps and human children can solve similar tasks. In a 2011 study, chimps and kids found out that they could put water into a tube to reach a peanut that was floating in a small amount of water at the bottom.
12．How did the crows get the snack in Sarah’s experiment?
A．By breaking the tube.
B．By dropping in erasers.
C．By standing on the wood.
D．By removing the wood.
13．What does the underlined part “the birds handled awkwardly” mean in Paragraph 4?
A．They were unable to tell different shapes.
B．They dropped objects only into narrow tubes.
C．They were not aware of the snack at first sight.
D．They mostly avoided the easier way to get the snack.
14．What does the text mainly focus on?
A．Stories of Aesop’s Fables.
B．The development of crows.
C．Crows’ intelligence.
D．Humananimal communication.
15．What do we know about crows in the passage?
A．Crows are almost as clever as firstgraders in some aspects.
B．Crows understand water displacement completely.
C．Chimps and children are much smarter than crows.
D．The story of the Crow and the Pitcher lacks evidence.
In the story of the Crow and the Pitcher from Aesop’s Fables, a thirsty crow drops stones into a narrow jar to raise the low level of water inside so he can take a drink.
Now scientists have evidence to back up that story. Crows actually do understand how to make water displacement(排水量) work to their advantage, experiments show. The results suggest that the birds are, at least in some aspects, as smart as firstgraders.
Researchers, led by Sarah Jelbert at the University of Cambridge, presented six crows with tubes containing water. Inside the tubes, a worm or a piece of meat on a piece of wood was floating, just out of reach of the crow. In front of the tubes, the researchers arranged several rubber erasers that would sink, and some plastic objects that would float. The crows found out that they could drop the erasers into the tubes in order to raise the water level and get their snack.
However, the birds handled awkwardly in experiments in which they could choose to drop objects in either a wide tube or a narrow one to get a snack, the researchers said. Dropping objects into a narrow tube would lift the water level by a greater amount and put the treat within reach after just two drops; while it took around seven drops to raise the snack to the same level in the wide tube. The crows obviously didn’t realize this, and most of them went for the wide tube first.
Previous studies showed that chimps and human children can solve similar tasks. In a 2011 study, chimps and kids found out that they could put water into a tube to reach a peanut that was floating in a small amount of water at the bottom.
12．How did the crows get the snack in Sarah’s experiment?
A．By breaking the tube.
B．By dropping in erasers.
C．By standing on the wood.
D．By removing the wood.
13．What does the underlined part “the birds handled awkwardly” mean in Paragraph 4?
A．They were unable to tell different shapes.
B．They dropped objects only into narrow tubes.
C．They were not aware of the snack at first sight.
D．They mostly avoided the easier way to get the snack.
14．What does the text mainly focus on?
A．Stories of Aesop’s Fables.
B．The development of crows.
C．Crows’ intelligence.
D．Humananimal communication.
15．What do we know about crows in the passage?
A．Crows are almost as clever as firstgraders in some aspects.
B．Crows understand water displacement completely.
C．Chimps and children are much smarter than crows.
D．The story of the Crow and the Pitcher lacks evidence.
