【推荐2】Ocean water is full of salt（盐）— and salt water can hold up（支撑）more weight than fresh water.（淡水）See for yourself!

You Will Need:

● 3 cups of warm water

● Measuring cup

● Wide-mouthed jar

● Salt

● Spoon（勺子）

● Raw potato

You Will Do:

1.Pour 1.5 cups of warm water into the jar.

2. Add 1/3 cup of salt.

3. Stir(搅拌) until the salt is completely dissolved.（溶解）

4. Add another 1.5 cups of water. Pour it slowly over the back of the spoon into the          jar so that the two liquid（液体） will not mix together.

5. Gently place the potato into the jar. Do not drop it.

What Will Happen:

The potato will sink（下沉）— but only halfway!

Why?

Salt water is heavier than fresh water, so it will stay on the bottom. The fresh water will remain on top.

The potato is heavier than the fresh water, but it is lighter than the salt water. That is why the potato will sink halfway down.

1. In which step of the experiment do you add the salt?

A．Step 1.	B．Step 2.
C．Step 3.	D．Step 4.

2. In Step 4 of the experiment, why do you pour the water over the spoon “slowly”?

A．It is easier to see what you are doing.

B．It pushes the fresh water to the bottom.

C．It will keep the water from coming out.

D．It will keep the liquids from mixing together.

3. In the experiment, what should you do right after you pour the water over the spoon?

A．Add the salt to the water.	B．Stir the salt into the water.
C．Place the potato in the jar.	D．Pour warm water into the jar.

【推荐3】What is the possibility of you having someone who looks just like you? Would it be a good thing? And if you did have one, would you want to meet them? Consider how often your facial features are used to recognize you. Your passport, ID card and driving licence all bare your face. To enter your workplace, you likely need to be recognisable. You may need your face to unlock your smartphone and possibly even need it to exclude you from being present at a crime scene.

The word “doppelganger” refers to a person who looks almost the same as you, basically sharing your features—those that you thought were unique to you and your identity (身份). Not an identical twin, as a doppelganger has no relation to you. The idea came from German folklore. A doppelganger was said to be a spirit-double that copied every human and beast on earth exactly.

So, let’s get real. What are the chances of you having one in the first place? There’s said to be a one in 135 chance of an absolute dead ringer for you existing anywhere in the world, so the chances are pretty low, despite folk wisdom promising you otherwise. And the chances of meeting? The mathematical certainty of finding this person is supposedly less than one in a trillion!

That said, these statistics may be a good thing. Historically, having a double hasn’t always been a positive.

Back in 1999, an innocent (无罪的)American man, undistinguishable from the real criminal, was sent to prison for robbery, where he stayed for 19 years. In the end, it turned out to be a case of mistaken identity. In a different case, a woman in New York was accused of trying to poison her doppelganger with deadly cheesecake so that she could steal her identity!

And, why are people interested in finding their possible doppelganger anyway? It may be helpful to look to the past when facial likeness showed kinship. Maybe one day you’ll meet your lookalike, but we understand that, after this, you possibly don’t want to!

1. In this passage, which of the following is your doppelganger?

A．facial features used to recognize you.

B．your face to unlock your smartphone.

C．a human who shares the similarity with you.

D．your identical twin.

2. What does the underlined phrases “these statistics” in Paragraph 4 refer to?

A．the low chances of having a doppelganger and the lower chances of meeting her/him.

B．German folklore and folk wisdom.

C．the historical data.

D．your recognizable information.

3. What did the main characters in the two cases mentioned have in common?

A．They were innocent.

B．Their doubles brought them pains.

C．They admired the life of others.

D．They had difficulty recognizing their own identity .

4. What’s the author’s attitude towards meeting someone who looks just like you?

A．promising.	B．relaxing.
C．unwanted.	D．meaningful.

【推荐1】Sometimes having a teenager at home can be a real headache. Many teenagers smoke, drink, wear strange hairdos and even fight. Basically, they are often taking risks.
Earlier studies have shown that teenagers are more likely to make _____decisions than people from any other age group, including children and adults. Is it that teenagers are too young to tell right from wrong? Not really. So what explains their risky behavior?
According to Laurence Steinberg, a professor at Temple University, US, the reason is that teens care a lot about how their peers (同龄人) view them – that’s the effect of “peer influence”, reported Science Daily.
As children enter their teenage years, they spend more time with their friends and classmates and also become more sensitive to their feedback (反馈). This sensitivity drives teenagers to concentrate on the short-term benefits of making risky choices and overlook the costs.
In a test, a group of teenagers were asked to play a video driving game. When they played with their friends watching, they took more chances and drove more carelessly because that would increase their possibility of winning. But when they played alone, they tended to drive more safely.
Why does pressure from peers have such a big influence on teens’ behavior?
As Steinberg sees it, a teenager’s brain is like a car with a good accelerator (油门) but a weak brake (刹车). The “accelerator”, the brain’s ability to notice the benefits of things, is fully developed by teenage years while the “brake”, the brain part related to controlling impulses (冲动) and long-term thinking, is still immature . When teens are under the pressure of being judged by their peers, they tend to push hard on the accelerator. Given how weak the brake is, it is likely that they are going to end up in a crash.
But the good news here, according to Steinberg, is that a violent teenager doesn’t necessarily become a violent adult. About two-thirds to three-quarters of violent youth grow out of it. “They get more self-controlled,” Steinberg told Live Science.
Also, people who haven’t committed a violent crime by age 19 are less likely to start doing it later, added Steinberg.
1. The underlined word “irrational” in the second paragraph is closest in meaning
to ______.

A．crazy

B．quick

C．careful

D．independent

2. Why are teenagers likely to take risks according to the text?

A．They are too young to tell right from wrong.

B．They are eager to challenge themselves.

C．They care a lot about what their peers think of them.

D．Their brains are more sensitive to thrilling events.

3. How does Steinberg explain the influence of peer pressure on teens’ behavior?

A．By performing an in-depth analysis.

B．By giving examples.

C．By using a metaphor (比喻).

D．By presenting research findings.

4. According to the text, with peers around them, teenagers tend to ______.

A．use more self-control

B．become more careful about what they do

C．perform better than when they are alone

D．focus more on short-term benefits

5. What can we conclude from the text?

A．Those who love taking risks are more likely to commit violent crimes.

B．The majority of teenagers become less violent when they grow up.

C．Violent teenagers often grow to be adults who cannot control themselves well.

D．People who are over 19 years old are less likely to commit a crime than Teenagers.

【推荐2】Consumption of ultra-processed foods (UPFs) has increased over the past 20 years. UPFs (超加工食品) contain few or no whole foods, are industrially produced, are ready-to-eat or ready-to-heat, and include additives (添加剂). The ultra-processing of food reduces its nutritional value. It has been known that higher UPF consumption is associated with overweight and heart disease. Now, research has been extended to examine its impact on mental health.

In a new study, over 72,000 participants who were at least 55 years old and didn’t have dementia (痴呆) at the start of the study were followed for an average of 10 years, during which they filled out questionnaires regarding their diet. By the end of the study, 518 people were diagnosed (诊断) with dementia. After adjusting for other factors that could affect risk of dementia such as age, gender, and heart disease, researchers found every 10 percent increase in daily intake of UPFs was associated with a 25 percent higher risk of dementia. They also found replacing 10percent of UPFs with unprocessed or minimally processed foods was associated with a 19 percent lower risk of dementia.

In another study, researchers found individuals who consumed the most UPFs had significant increases in the symptoms (症状) of mild depression, “mentally unhealthy days”, and “anxious days”. Eric Hecht, Founder and Executive Director of the Institute of Etiological Research, said, “More than 70 percent of packaged foods in the US are classified as UPFs and represent about 60percent of all calories consumed by Americans. Considering the degree of exposure to and effects of UPF consumption, this study has great significance in clinical practice and public health. It might help improve future development of dietary guidelines.”

Facing such alarming data, maybe it’s time for Americans to reconsider their food choices. Researchers recommend taxes on UPFs and carrying out policies to reduce the consumption. They also support programs and policies to increase the availability and affordability of whole foods, especially among disadvantaged populations.

1. What do we know about UPFs?

A．They have no nutritional value.	B．They are ready-made and instant foods.
C．They are cheap and mass-produced.	D．They serve as additions to our daily diets.

2. What’s Eric Hecht’s attitude toward the new study?

A．Positive.

B．Negative.

C．Ambiguous.

D．Doubtful.

3. What do researchers suggest doing?

A．Collecting higher taxes on UPFs.	B．Decreasing UPFs’ consumption in diet.
C．Focusing on the nutrient content of foods.	D．Increasing public awareness of whole foods.

4. Which can be a suitable title for the text?

A．Public Health Response to UPFs	B．Physical Disorders Linked to UPFs
C．Rising Consumption of UPFs in the US	D．Negative Effects of UPFs on Mental Health

【推荐3】A study of a million UK women, published today in The Lancet, has shown that happiness itself has no direct effect on mortality, and that the widespread but mistaken belief that unhappiness and stress directly cause ill health came from studies that had simply confused cause and effect. Life-threatening poor health can cause unhappiness, and for this reason unhappiness is associated with increased mortality. In addition, smokers tend to be unhappier than non-smokers. However, after taking account of previous ill health, smoking, and other lifestyle and socio-economic factors, the investigators found that unhappiness itself was no longer associated with increased mortality.
The lead author, Dr Bette Liu, now at the University of New South Wales, Australia said: "Illness makes you unhappy, but unhappiness itself doesn't make you ill. We found no direct effect of unhappiness or stress on mortality, even in a ten-year study of a million women."
As in other studies, unhappiness was associated with deprivation, smoking, lack of exercise, and not living with a partner. The strongest associations, however, were that the women who were already in poor health tended to say that they were unhappy, stressed, not in control, and not relaxed.
The main analyses included 700 000 women, average age 59 years, and over the next 10 years these women were followed by electronic record linkage for mortality, during which time 30 000 of the women died.
After allowing for any differences already present in health and lifestyle, the overall death rate among those who were unhappy was the same as the death rate among those who were generally happy. The study is so large that it rules out unhappiness being a direct cause of any material increase in overall mortality in women.
This was true for overall mortality, for cancer mortality, and for heart disease mortality, and it was true for stress as well as for unhappiness.
1. The word “mortality” in the passage means   .

A．richness	B．relaxation
C．death	D．morality

2. According to the passage, which of the following statements is true?

A．Unhappiness will definitely make a person ill.

B．Unhappiness doesn’t necessarily make you ill.

C．Unhappiness is not associated with lack of exercise.

D．The death rate among those unhappy people is greater.

3. It’s wrongly believed that ________.

A．unhappiness itself is not associated with increased mortality

B．there is no direct link between unhappiness and mortality

C．ill health directly causes unhappiness and stress

D．ill health directly results from unhappiness and stress

4. The writer’s attitude towards the result of the study is __________.

A．disappointing	B．indifferent
C．subjective	D．objective