Food storing is common in members of the crow (乌鸦) family. A new study tested the birds outside this naturally occurring behaviour, which may have evolved (进化) specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to recover food. So the researchers tested whether the birds could store and recover a tool so they could get it at their food after a gap of 17 hours—something we wouldn't expect them to do naturally. But they were able to instantly select the tool out of a number of unnecessary items.
In another experiment, the researchers taught crows to select a token (礼品券) from a number of items so that they could then exchange for food. Again, the birds then showed that they could plan for the future using this new behaviour. This is different from all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that chimpanzees select, transport and save appropriate tools for future needs.
These studies have shown that animals can plan for the future—but they left an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviours.
But the new research provides the first evidence that animal species can plan for the future using behaviour that doesn't typically occur in nature. This supports the view that at least some cognitive abilities in animals don't evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviours flexibly across problems in a similar way to humans. We need to investigate how flexible behaviour evolved. Then we might be able to see how crows' ability to plan for the future fits in with their broader cognitive powers.
本文通过乌鸦，谈论有关动物的进化，但是目前还不清楚它们是怎样进化的。
1．What's the new finding about some crows according to Paragraph 1?
A．They can store food.
B．They can use tools to recover food.
C．They can store and recover tools.
D．They can select and store food.
答案：C
解析：细节理解题。根据第一段中Some crow species are known to naturally use tools to recover food...But they were able to instantly select the tool out of a number of unnecessary items.可知，对乌鸦的新发现是：他们可以存储和恢复工具。故选C。
2．What are crows trained by scientists to do when given a token?
A．Reject it casually. B．Exchange it for food.
C．Save it as their food. D．Build a nest with it.
答案：B
解析：细节理解题。根据第二段第一句In another experiment, the researchers taught crows to select a token (礼品券) from a number of items so that they could then exchange for food.可知，训练乌鸦用奖品券来交换食物。故选B。
3．What do scientists think of the studies that animals can plan for the future?
A．They are controversial.
B．They are disappointing.
C．They are contradictory.
D．They are convincing.
答案：A
解析：推理判断题。根据第三段第一句These studies have shown that animals can plan for the future—but they left an important question open for debate.可知，科学家们关于动物可以为未来做计划的研究是有争议的。故选A。
4．What can be inferred about cognitive abilities in animals?
A．They develop only with age.
B．It is unclear how they've evolved now.
C．No animals but crows benefit from them.
D．Planning for the future helps their evolution.
答案：B
解析：推理判断题。根据最后一段中We need to investigate how flexible behaviour evolved.可知，还不清楚它们是怎样进化的。故选B。
