【推荐1】Jackdaws (寒鸦) switch between two sets of flocking (聚集) rules with differing results, new research has found. Flocks flying to winter roosts (居住地) are orderly no matter how many birds they contain; those trying to fight off enemies are initially disorganized when their numbers are small and then suddenly flip to order once enough birds join in.

Swimming bacteria, marching locusts, schooling fish and flocking birds all function as units. This phenomenon can emerge when individual agents following the same rules come together, says Alex Thornton, who studies cognitive evolution at the University of Exeter in England. “We got used to thinking of collective behavior as this almost physical phenomenon,” he says. “So the idea that animals might actually change the rules that they use when their environment and what they’re trying to achieve are different is quite novel and exciting.”

The researchers filmed flocking wild jackdaws in Cornwall, England, with four high-speed cameras, charting individuals’ positions and flying courses. Of the 16 flocks recorded, six were “transit flocks”— jackdaws returning to their roosts on winter evenings. In these groups, regardless of size, each jackdaw adjusted its course based on a fixed number of neighbors and always maintained order.

To initiate “mobbing flocks,” the researchers presented to groups of jackdaws a fake fox holding a fake, flapping bird and played alarm calls that the birds commonly use to warn other birds against enemies. In this context, jackdaws instead navigated by tracking all birds that were within a fixed distance. “With these rules, you have emergence of order from mess,” Thornton says. “Small flocks are disorganized. When the density of the flock reaches a certain level, suddenly there is order — much like how a gas transitions into a liquid.” These transitions have never been observed in birds before, he adds.

“What our work shows is that you cannot ignore the external environment in trying to model collective behavior in biological systems,” says Nicholas Ouellette, a physicist at Stanford University and co-author on the study. Drawing inspiration from jackdaws, he says, engineers could someday use context-dependent responses to build teams of drones that work together for firefighting, surveying and search-and-rescue missions: “It allows you to think about designing systems that are more flexible, that can change the rules to make the behavior more proper.”

1. What does Alex Thornton’s new research find about Jackdaws?

A．They vary the rules with which they gather.

B．They function as units while flying to winter roosts.

C．They tend to fly apart when meeting with enemies.

D．They get disorganize to wait for more birds to join in.

2. Which of the following statements is true of “transit flocks”?

A．They are normally big in size.

B．They are always in good order.

C．The members seldom changed their courses.

D．The members find direction by tracking faraway birds.

3. It can be inferred from the passage that the transitions of a gas into a liquid are processes in which ________.

A．mess turns into order

B．density remains the same

C．changes often happen slowly but steadily

D．molecules keep a fixed distance from each other

4. Nicholas Ouellette is quoted in the passage in order to ________.

A．highlight the flexibility of flocking birds

B．reveal how context-dependent responses occur

C．show how the research findings can be applied to different fields

D．call attention to the importance of the external environment

【推荐2】Twelve prized camels have been disqualified from a beauty contest in Saudi Arabia after their owners tried to beautify their looks with Botox(肉毒杆菌素).

Thousands of camels are paraded at the King Abdulaziz Camel Festival to be judged on their shapely lips and humps. The festival, which also features camel racing and camel milk tasting, has combined prize money of $57 million.

This year’s event has been stuck in scandal after the 20 million Saudi riyals (里亚尔，货币单位) in prize money for each category tempted some owners to cheat.

The key features in camel beauty are considered to be delicate ears and a big nose. Judges are also looking for perfectly placed humps, muscular physiques and leathery mouths. But there are strict rules against the use of drugs in the lips, or shaved or clipped body parts.

Ali Al Mazrouei, the son of a top Emirati breeder, said Botox was used for the lips, the nose and even the jaw. “It makes the head more inflated, so when the camel comes, it’s like ‘Oh look at how big that head is. It has big lips, a big nose’,” he said.

In the lead up to the festival, Saudi media reported that a vet had been caught giving camels plastic surgery including Botox injections and reducing the size of their ears.

Chief judge Fawzan Al-Madi said the camel was “a symbol of Saudi Arabia”. “We used to preserve it out of necessity; now we preserve it as a pastime,” he said. The camel beauty contest was first held in 2000 and last year was relocated from a remote desert area to a permanent venue north of the capital, Riyadh.

1. Why did some people cheat in the camel beauty contest?

A．They wanted to get the big prize.

B．They intended to show off their camels.

C．They were proud of their camels’ humps.

D．They expected their camels to win in racing.

2. What is focused in the fourth paragraph?

A．The goal of the contest.	B．The rules for the judges.
C．The standards of judgement.	D．The kinds of different camels.

3. Which of the following isn’t considered a feature of camel beauty?

A．Big lips.

B．Big ears.

C．Big heads.

D．Big noses.

4. What can we infer from the last paragraph?

A．Arabians find it tiring to raise camels.

B．People in Saudi Arabia depend on camels to live.

C．Saudi government takes the camel festival seriously.

D．Camels were raised for fun in the past in Saudi Arabia.

【推荐3】Three years ago our yellow dog, Abby, passed away due to old age. My experience with my beloved dog became useful years later as I considered getting a new dog—a hiking and adventure companion, a nap buddy (午休伙伴), a watchdog: everything Abby used to be for my family and I when I was growing up.

The process of adopting a puppy (幼犬) can be long and hard. But thanks to large retailers (零售商) like Petco and their weekend “adoption days”, I was able to walk away with my puppy after only a $300 payment, a signature and verbal commitment to take care of her to the best of my abilities.

I wasn't entirely “prepared” for my puppy when I got her, and I can't say my parents were for sure on board when I adopted her, knowing she'd outgrow my living conditions and need the sizable yard and mountain access only my parents' house could provide her with. But I took the leap, supplied her with everything she could possibly need to be happy and develop properly, set up a vet appointment and made a commitment to myself and her to do whatever I had to do to make sure she grew up right.

My dad actually jokes now that he's become a grandpa before he thought he would, and I think there's some truth to that I'm not the mother of a human being yet, but I can draw some similarities between taking care of a baby and raising a puppy. Koda wakes up several times a night to go to the bathroom, eats her pricey puppy food, has accidents on the carpet and in my bed, cries when I'm not around and stops me from concentrating on my homework. Since adopting her, I can't do anything without first considering how my actions and choices will affect my dog.

Puppy parenting isn't easy, and that's part of why it's so rewarding.

1. What did the author consider important when thinking about adopting a new dog?

A．Getting her parents' approval.	B．Getting a yellow one once again.
C．Getting one like her previous dog.	D．Getting one that didn't demand much care.

2. What does Paragraph 2 tell us about the authors adopting her dog?

A．Its process was long and hard.

B．It was easier than she had thought.

C．It got some money support on “adoption days”.

D．It cost more money than she expected.

3. What problem did the author face after adopting her dog?

A．Her living place didn't suit the dog.

B．Her parents didn't really love the dog.

C．She couldn't afford the expensive puppy food.

D．She had trouble in setting up vet appointments.

4. How did the author most probably find keeping a dog?

A．Tiring but worthy.	B．Easy and rewarding.
C．Exhausting and useless.	D．Terrifying but exciting.