【推荐1】Some people sit outside for hours without getting bitten by mosquitoes, but it always seems like you’re being eaten alive within minutes of stepping outdoors.     1     According to Smithsonian Magazine, around 20 percent of people in the world are especially tasty to mosquitoes.

A popular belief claims that mosquitoes prefer certain blood types.     2    . According to Jonathon Day, a professor of medical entomology(昆虫学) at the University of Florida in the US, the truth is not so complicated.     3    

While flying along, mosquitoes use their sense of smell to find possible targets. They find victims by smelling the carbon dioxide(CO₂) breathed out by humans and animals. Joop van Loon, an entomologist at Wageningen University in the Netherlands, told Live Science, “Mosquitoes start aiming themselves to CO₂ and keep flying upwind(逆风) as they sense higher thickness.     4     “This is why kids don’t get bitten as much as adults,” US professor Ted Rosen told Science Alert.

    5     According to Live Science, mosquitoes can lock onto targets from up to 50 meters away. At this distance, what we wear has a huge effect. Due to their vision, people wearing dark colors are more likely to become targets.

A．If this is you, you are not alone.

B．You’re the most unfortunate one.

C．The two most important reasons attracting a mosquito are smell and sight.

D．But the fact is that they simply can’t tell your blood type from a faraway place.

E．Besides carbon dioxide, the color of the clothes you wear also plays a role in attracting mosquitoes.

F．Generally, scientists recommend that we use chemicals and wear light-colored clothing to keep off mosquitoes.

G．Therefore, larger people, who simply breathe out more of the gas over time tend to attract more mosquitoes.

【推荐2】Anyone who commutes（通勤）by car knows that traffic jams are an unavoidable part of life. But humans are no alone in facing potential backups.

Ants also commute— between their nest and sources of food . The survival of their habitats（栖息地）depends on doing this efficiently.

When humans commute, there's a point at which cars become dense（稠密）enough to slow down the flow of traffic, causing jam. Researchers wanted to know if ants on the move could also get stuck. So they regulated traffic density by building bridges of various widths between a colony（群体）of Argentine ants and a source of food. Then they waited and watched, trying to find out at what point they are going to have a traffic jam.

But it appears that that never happened. They always managed to avoid traffic jam. The flow of ants did increase at the beginning as ants started to fill the bridge and then levelled off at high densities. But it never slowed down or stopped, even when the bridge was nearly filled with ants.

The researchers then took a closer look at how the behaviour of individual ants impacted traffic as a whole. And they found that when ants sense overcrowding, they adjust their speeds and avoid entering high-density areas, which prevents jams. These behaviors may be promoted by pheromones, chemicals that tell other ants where a path is. The ants also manage to avoid crashing into each other at high densities, which could really slow them down.

Can ants help us solve our own traffic problems? Not likely. That's because when it comes to getting from point A to point B as fast as possible, human drivers put their own goals first. Individual ants have to be more cooperative in order to feed the colony. But the research could be useful in improving traffic flow for self-driving cars, which can be designed to be less like selfish humans —and more like ants.

1. What does the underlined word "this" in paragraph 2 refer to?

A．Commuting.

B．Finding food.

C．Surviving,

D．Avoiding jams.

2. How did the researchers control the traffic density of the commuting ants?

A．By observing closely.	B．By finding out the dense points.
C．By controlling the widths of their path	D．By regulating the numbers of the colony.

3. How can ants avoid traffic jam according to the research?

A．They follow a special route.

B．They level off at high densities.

C．They never stop or slow down on the way.

D．They release natural chemicals to adjust speeds.

4. What can we infer from the last paragraph about the finding?

A．It can help solve traffic problems.

B．It is not what researchers expected.

C．It shows the importance of good teamwork.

D．It is of no use to the development of self-driving cars.

【推荐3】Twenty years ago, I became involved in pet therapy (治疗) work. As digging deeper into the job, I had an urge to be a recorder of their daily work to let more and more people know their efforts and contributions. After all, they could not say our languages. It was when I got familiar with the work that I got my golden retriever puppy (金毛寻回犬), whom I named Angel. As she matured and went through obedience training, I realized that she would be a good partner.

Angel is ten now and still works every week. As a rule, she visits two hospitals, a day care for the elderly, and our library’s PAWS for Reading program. Angel has also helped out at a children’s special-needs camp. She is so popular that everywhere we go people recognize her, especially the kids she has worked with.

We have seen some very special things through our pet therapy work. I brought Angel to our local hospital to visit a woman who was completely paralyzed (瘫痪的) on her right side from a stroke. One day, my husband, Jack asked her if she wanted to give Angel a treat. She nodded and gently took the treat, raised her right hand and started petting Angel. Her friend was in the room and said, “She hasn’t been able to move that hand since she had her stroke!”

Somehow it seems appropriate that when Angel visits the hospital, she also performs tricks for the patients with her paws. The best one is when she crouches on the floor and crosses her paws. She stays still and doesn’t move until Jack says “Best wishes”. It’s the best wishes for all the people Angel meets as well as for her.

1. Why does the author want to be a recorder?

A．Pets cannot record themselves.	B．Pets should be highly praised.
C．Pets’ labor should be made aware of.	D．Pets daily work is important.

2. How is Angel’s work?

A．Busy but rewarding.	B．Interesting but tiring.
C．Funny and amusing.	D．Important and demanding.

3. What did Angel do for the paralyzed woman?

A．She cured her disease.	B．She visited her at times.
C．She gave her best wishes.	D．She played tricks on her.

4. What is the best title for the passage?

A．A loyal dog.	B．Selfless love.
C．A silent angel.	D．Great devotion.