1 . In a story from Aesop’s Fables (伊索寓言), a thirsty crow (乌鸦) drops stones into a narrow bottle to raise the low level of water inside so he can take a drink.
Now scientists have experiments to back up that story. The experiments show that crows actually do understand how to make water displacement (排水量) work to their advantage. The results suggest that the birds are, at least in some cases, as smart as first-graders.
Researchers, led by Sarah Jelbert at the University of Cambridge, presented six crows with bottles, containing water. Inside the bottles, a piece of meat on a piece of wood was floating (漂浮), just out of reach of the crows. In front of the bottles, 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 bottles in order to raise the water level and get their meat.
However, the birds were awkward in experiments in which they could choose to drop objects in either a wide bottle or a narrow one to get the meat, the researchers said. Dropping objects into a narrow bottle 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 meat to the same level in the wide bottle. The crows obviously didn’t realize this, and most of them went for the wide bottle first.
Previous studies showed that chimps (大猩猩) and human children can solve similar tasks. In a 2011 study, chimps and kids found out that they could put water into a bottle to reach a peanut that was floating in a small amount of water at the bottom.
1. What does the text focus on?
| A．The truth of Aesop’s fables. | B．Crows’ intelligence. |
| C．The development of crows. | D．Human-animal communication. |
2. How did the crows get the meat in Sarah’s experiment?
| A．By breaking the bottle. | B．By dropping erasers. |
| C．By standing on the wood. | D．By removing the wood. |
3. What does the underlined part “the treat” refer to?
| A．The bottle. | B．The objects. | C．The meat. | D．The water. |
4. What does the experiments in Paragraph 4 want to prove?
| A．Crows are unable to tell different shapes. |
| B．Crows prefer narrow bottles. |
| C．Crows are good at counting numbers. |
| D．Crows are not clever all the time. |
5. Examples of chimps and kids are used to show that ________.
| A．crows are as smart as them. |
| B．crows are smarter than them. |
| C．crows are less smart than them. |
| D．crows can not be compared with them. |
