1 . New Caledonian crows are well-known for using different types of tools for preying (捕食) from tree holes and other hiding places. While they firmly hold their tools in the bill, they need to put them down to eat. This is when crows are at risk of losing their tools by accidentally dropping them or having them stolen by other crows.
In an earlier study, researchers in the UK had discovered that crows keep their tools safe when not needed, using one of two “safekeeping” strategies—they either securely hold them trapped underfoot, or temporarily put them into a nearby hole or behind bark. But are crows more careful when handling particularly valuable tools?
“Many of us will fuss (大惊小怪) about a brand-new phone, making sure it does not get scratched, dropped or lost. But we may handle an old phone with a cracked screen quite carelessly,” said lead author Barbara Klump from the Max Planck Institute of Animal Behavior, Germany.
Crows at one of the team’s long-term study sites use two different kinds of stick tools: complex hooked tools and basic non-hooked tools. The former are painstakingly crafted from a relatively scarce plant species, while the latter are simply twigs (细枝) sourced from the forest floor. “Hooked tools are not only more costly to obtain, but they are also much more efficient,” explained Barbara Klump. “Depending on the foraging (觅食) task, crows can get prey with these tools up to ten times faster than with non-hooked tools.”
In their new study, the researchers now discovered that New Caledonian crows are more likely to keep valuable hooked tools safe between uses than the more basic non-hooked tools. “It was exciting to see crows are just a bit more careful with tools that are more efficient and more costly to replace. This suggests that they have some conception of the relative value’ of different tool types,” noted study co-author James St Clair.
This is the first study to investigate how animals handle and store tools of different kinds, providing a new way to measure how much they value these objects.
1. Why are phones mentioned in paragraph 3?| A．To indicate the necessity of phones in our daily life. |
| B．To emphasize people’s attachment to their old devices. |
| C．To stress the similarity between humans and crows. |
| D．To show people’s improper attitude to old things. |
| A．It can be gotten easily. | B．It can be adjusted freely. |
| C．It can make crows’ foraging more productive. | D．It can prevent crows from danger. |
| A．Their secret hiding places. | B．Their unusual eating habits. |
| C．Their creation of complex tools. | D．Their treatment of valuable tools. |
| A．Crows Use Strategies to Gain Valuable Tools |
| B．Crows Learn to Use Special Tools for Preying |
| C．New Discovery of How Crows Make Tools |
| D．New Caledonian Crows Keep Favorite Tools Safer |
增加：在缺词处加一个漏字符号(∧)，并在其下面写出该加的词。
删除：把多余的词用斜线(\)划掉。
修改：在错的词下划一横线，并在该词下面写出修改后的词。
注意：1. 每处错误及其修改均仅限一词；
2. 只允许修改10处，多者(从第11处起)不计分。
Have you wondered how your body knows when to wake up or why you need the toilet less at night? Influencing by light, body clocks use the sun to help your body to run on time. They repeat every 24 hours and almost every living thing has them. When the sun shines across the window in the morning, your body clock tells you it’s time to wake up. When it’s dark, your body feels sleepy. Not listening to your body clock, such as by going to bed late can mess up your sleep cycle, that makes you tired the next day. Scientists have found body clocks help our whole body run smooth. The Sleep Charity, which helps people to sleep better, recommend sticking to regular sleep patterns. So you’re a night owl who stays up late or a morning lark who likes to get up early, try going to bed and get up at the same time every day. It also suggests getting lots of natural lights in the morning. Even if the sky is cloudy and grey, this can reset your body clock and make you to feel more awake.
In Xixian county, located in Linfen, Shanxi province, a smart pear orchard (果园)
In this orchard, every pear is given
So far, Xixian
According to Wang, the platform not only helps with production but also promotes sales, as its tracking system can collect first-hand marketing feedback data. Pear farmers can learn about the market demand through the system to
7 . Australian scientists have started vaccinating (接种疫苗) wild koalas against the disease Chlamydia (衣原体病) in an ambitious trial in New South Wales (NSW). They want to test a way to protect the animals against the widespread condition that causes blindness, the inability to have babies, and death.
“It’s killing koalas because they become so sick that they can’t climb trees to get food, and females are unable to have babies,” said Dr. Samuel Phillips, a microbiologist at the University of the Sunshine Coast.
Around half of the wild koala population in the Northern Rivers region of NSW—about 50 animals—will be caught and vaccinated. “We want to evaluate what percentage of the koalas we need to vaccinate to meaningfully reduce infection and disease,”said Dr. Phillips.
The first koalas were caught and vaccinated in March and the effort is expected to last about three months. Researchers use telescopes to spot koalas in the trees, then build fences around the tree bases with doors leading into cages. After a few hours or days, the koalas climb down from one tree to seek tasty leaves on another and wander into the harmless traps.
After a cheek-up to make sure the animals are in good condition, researchers give them anaesthesia (麻醉) to make them sleep before they administer the vaccine. They watch the koalas’health for 24 hours after they wake up to make sure there are no side effects. The goal is to vaccinate healthy koalas to prevent them from becoming infected with chlamydia. The researchers mark the koalas’backs with pink dye so the same animals aren’t caught twice.
It is not known what caused koalas to catch chlamydia, but the scientists believe it was probably from exposure to the infected sheep and cattle. It spreads when koalas mate, or it can be passed from a mother to her babies.
1. Why was the ambitious trial started?| A．To establish a wildlife reserve. | B．To attract the tourists of all ages. |
| C．To test a newly developed vaccine. | D．To reduce infection among koalas. |
| A．Uncaring. | B．Doubtful. | C．Concerned. | D．Cautious. |
| A．Dangerous. | B．Demanding. | C．Simple. | D．Useless. |
| A．Why koalas suffer from the disease. | B．How researchers recognize koalas. |
| C．What a koala family largely feeds on. | D．When a female koala can have a baby. |
| A．as | B．when | C．but | D．while |
