【推荐2】Health advice on hand sanitizers

Antibacterial hand sanitizers（免洗洗手液）are marketed as a good alternative（替代品）when soap and water are not available. Manufacturers say that their sanitizers kill 99.9 percent of germs（细菌）, but research suggests that this not the case.

How do hand sanitizers work?

Most sanitizers are alcohol-based; they work by removing the outer layer of oil on our skin, then the alcohol kills the bacteria.

However, Barbara Almanza, associate professor at Purdue University, notes that hand sanitizers do not significantly reduce the amount of bacteria, and in some cases, can increase it.

So the question arises, how can manufacturers say sanitizers kill 99.9 percent of bacteria?

How can manufacturers make the 99.9 percent claim（声称）?

Manufacturers test their products on bacteria-tainted surfaces. In this controlled environment, hand sanitizers do kill 99.9 percent of bacteria. However, the human hand is a lot more complex and goes through a lot of different changes in a day compared to a controlled surface.

These tests allow manufactures to obtain consistent results. But , in reality, how effective are hand sanitizers in killing bacteria in everyday life?

Hand sanitizer VS hand soap and water

Almanza says that soap and water are the best way to clean your hands. Hand sanitizer cannot and should not be a direct replacement.

However, they are a useful alternative. To effectively kill bacteria, studies recommend that people use sanitizers that are at least 60 percent alcohol. Also, sanitizers won’t work if you have dirty hands, so wipe them with a tissue or napkin before sanitizing.

What about antibacterial soaps?

Research has shown that regular soap is just as effective as antibacterial soap in reducing bacteria-related illnesses.

In fact, some consumer antibacterial soap may increase some bacteria’s resistance to antibiotics（抗生素）, making them more dangerous.

Other studies show that overly clean environments will negatively affect children by preventing their immune（免疫的）system development. Children need to fight off common germs to develop their immune systems.

1. What do we know about antibacterial hand sanitizers?

A．Most work similarly to hand soap.

B．Most use alcohol to kill the bacteria.

C．Most can’t remove oil on our skin.

D．Most bring more bacteria to people.

2. What problem does the research find about the manufacturers’ claim?

A．Their conclusion isn’t drawn from real-life environments.

B．Manufacturers don’t test their products before selling them.

C．Their products don’t kill the bacteria people usually have.

D．Manufacturers don’t tell the public how they get their conclusion.

3. Which is the first choice to clean your hands, according to Almanza?

A．Wet tissue.

B．Hand sanitizer.

C．Hand soap and water.

D．60 percent alcohol and water.

4. What does the text tell us about antibacterial soaps?

A．Some contain dangerous antibiotics.

B．They kill more bacteria than regular soaps.

C．They might be harmful for children’s development.

D．Some are proved to increase the amount of bacteria.

【推荐1】Nine mini cheetahs robots appeared in the field to show their athletic abilities. The four-legged machines, mini versions of the larger and heavier Cheetah 3, began with a warm-up run across the field.

Though they may be similar to their predecessors(原先的事物), the new four-legged machines are much more advanced. Weighing just nine kilograms, the robots can bend and swing their legs wide, giving them the ability to walk either right-side-up or upside down. They can also travel through uneven places at about twice the speed of an average person’s walking pace and quickly right themselves if kicked to the ground and perform unbelievable 360-degree backflips(后空翻) from a standing position.

Unlike the Cheetah 3, the main robots are built using cheap and easy to find parts. This means that if an arm or a motor breaks, it can be easily replaced. “If you wanted to add another arm, you could just add three or four more of these motors,” said lead developer Benjamin Katz, “You could put these parts together, almost like Legos.”

The team, which currently has ten of the four-legged machines, plans to build additional units in other university robotic labs. “A big part of why we built this robot is that it makes it easy to experiment and just try crazy things, because the robot is very strong and doesn’t break easily, and if it does break, it’s easy and not very expensive to fix, ” said Katz.

He believes that this will enable other engineers to teach the robots different skills. “Eventually, I’m hoping that we could have a robotic dog race through an obstacle course, where each team controls a mini cheetah with different ways, and we can see which strategy is more effective. That’s how you accelerate research,” said Katz.

The team’s reason for developing the robots extends beyond entertainment. They hope that someday packs of “cheetahs” will assist first respondents with search and recovery missions following natural disasters like earthquakes, work alongside firefighters, and even respond to military emergencies.

1. Which of the following best describes the mini robot?

A．Delicate.	B．Portable.
C．Complex.	D．Flexible.

2. Why are cheap materials used for the mini robot?

A．To test it out in other fields.	B．To produce it on a large scale.
C．To make sure it’s easy to repair.	D．To make people afford to buy it.

3. What’s the main purpose of making the “cheetahs”?

A．To replace firefighters.	B．To entertain people in a way.
C．To bring more convenience to people.	D．To help people in dangerous situation.

4. Where is the text most likely from?

A．A diary.	B．A magazine.
C．A novel.	D．A guide book.

【推荐3】If you’re someone who has been worrying about the rise of the robots—hold on there just a second, and let them help you impress your friends with some newfound skills in a foreign language. Using artificial intelligence (AI) to help us learn and improve those skills is not new—some of the online language tools we turn to every day are powered by AI.

But as new technologies flood into the market, now is a great time to take advantage of the tech. And according to experts, these tools aren’t replacing teachers—they’re making their lives easier. One of the things that stops some of us from practicing speaking in a new language is a lack of self-confidence. AI can help—chatbots don’t judge you. Of course, teachers don’t either, but for some people, communicating with a bot may erase that fear of failure or shyness.

The latest chatbots use something called natural language processing that allows them to understand human speech or writing, providing a human-like response right away. While chatbots are extremely useful for learners working individually, teachers can also offer course material and ask an AI system to produce personalized textbooks for groups of students. The AI can also provide feedback (反馈) in seconds—gone are the days of waiting a week for work to be graded.

Past online language tools and games were able to tell you when you were wrong, but they weren’t always able to explain why. Now, not only has that changed, but the explanations are detailed and immediate. But this is not to underestimate the role of the teacher, who can use the technology to help learn more about the strengths and shortcomings of their students and personalize their teaching.

So, if you want to impress your friends with your perfect speech, don’t be afraid of AI. Just think of it as a useful tool for both teachers and language learners, which will give you more time and space to enjoy learning something new!

1. What is the main idea of the article?

A．The dangers of Al-robots.

B．The history of online language tools.

C．The benefits of AI in language learning.

D．The role of teachers in the modern classroom.

2. Why might someone prefer communicating with a bot?

A．Because bots grade work faster.

B．Because bots provide textbooks.

C．Because bots are more knowledgeable.

D．Because bots may remove the fear of failure or shyness.

3. What is the benefit of AI producing personalized textbooks?

A．It saves time for teachers.	B．It reduces the cost of education.
C．It meets individual students’ needs.	D．It provides detailed lesson plans.

4. What word might replace the underlined word “shortcoming” in paragraph 4?

A．weakness.

B．awareness.

C．witness.

D．darkness.