1 . All evidence points to the fact that Mars once had flowing water, but numerous flybys, orbiters and landers have confirmed one undeniable fact — any liquid (液体的) water that was once on its surface is now long gone.

One idea, the Mars Ocean Hypothesis, suggests that Mars not only had some liquid water, but a lot of it. But the new study’s co-author Kun Wang says his team’s finding pours cold water on it.

“Mars’ fate (命运) was decided from the beginning.” Wang, an assistant professor of Earth and planetary sciences, said in a statement. That’s because the lower mass and gravity of Mars makes it easier for volatile (挥发) elements and compounds such as water to escape from its surface into space.

The researchers looked at 20 Martian meteorites (陨石) ranging in age from about 200 million years old to 4 billion years, dating back to a time when the solar system was still in the chaos of formation. The researchers analyzed water behaves in much the same way, indicating that most of it would have been lost to space during the formation of Mars.

The liquid water that did remain on the Martian surface carved out the riverbeds and other formations that we see there today, Wang says. But that water, too, would likely have disappeared had it not been trapped as ice at the Martian poles as the climate on the planet became colder, he notes.

“This does probably indicate a lower limit on size for a planet to be truly habitable,” Wang says, “Understanding that lower limit is important — there are lines of evidence that small planets are more common than big ones, so if the small ones are dry, then there are fewer habitable (适于居住的) worlds out there than we thought.”

2 . Research shows people have a tendency to seek out information during uncertain times — it’s a natural coping mechanism (机制). But is continuous information-seeking on social media, sometimes called doomscrolling (末日刷刷刷), helpful during a pandemic, or any time?

Research on the effects of bad news on mood suggests exposure to negative COVID news is likely to be dangerous to our emotional well being. For instance, one study conducted in March 2020 involving more than 6,000 Americans found that the more time participants spent consuming COVID news in a day, the unhappier they felt.

These findings are striking but leave a few key questions unanswered. Does doomscrolling make people unhappy, or are unhappy people just more likely to doomscroll? How much time spent doomscrolling is a problem? And what would happen if, instead of doomscrolling, we were “ kindness scrolling ” — reading about humanity’s positive responses to a global crisis?

To find out answers to these questions, researchers conducted a study where they showed hundreds of people real-world content on either Twitter or YouTube for two to four minutes. The Twitter feeds and YouTube videos featured either general news about the COVID, or news about kindness during COVID. Researchers then measured these participants’ moods using a questionnaire, and compared their moods with participants who did not engage with any content at all.

People who were shown general COVID-related news experienced lower moods than people who were shown nothing at all. Meanwhile, people who were shown COVID news stories involving acts of kindness didn’t experience the same decline in mood, but also didn’t gain the boost in mood they’ d predicted. These findings suggest that spending as little as two to four minutes consuming negative news about COVID-19 can have a negative impact on our mood.

Researchers are still working on what people can do to look after themselves, and make time on social media more pleasurable.

3 . Screen time is often considered the enemy when it comes to teaching kids to be active. However, a new research found that for 9 and 10 years old children greater social media use was related to some positive effects, including increased physical activity, less family conflict (冲突) and fewer sleep problems.

The findings come from an analysis of data from about 4,500 young people and their parents collected by the Adolescent Brain Cognitive Development study. The study gathered information about how young people’s brains develop.

In the study, children self reported activities like watching TV, texting or visiting social media sites — and the time spent on each. They were also asked about whether they play mature (成年的) video games. They rated their time on them as never, once in a while and all the time. Kids and parents report on family conflict. Parents also kept track of how well the kids slept and filled out a checklist that assessed (评定) their children’s behavior.

The results haven’t been published yet, but are being presented Tuesday at the Research Society on Alcoholism in San Diego. Previous research has been done. largely in older kids or teenagers with less focus on younger kids. Communities and social networks can have beneficial effects, so kids who are using social media to build connections may see positive outcomes.

Do these findings mean that parents should ban TVs and sign their kids up for Twitter? Probably not. Psychologist Chris Ferguson of Stetson University says that the differences identified in the research are small.

4 . Famous Israeli gastronome (美食家) Michal Ansky is a professional taster and a Master Chef judge. So when she was invited to the world’s first public blind taste test setting lab-grown chicken into competition against a conventionally raised product, she was confident that she would be able to tell the difference.

Surrounded by cameras at a restaurant bar, she tasted from two dishes, labeled A and B. A team of lawyers looked on, tasked with making sure that the tasting truly was blind. Even the chef who sautéed (嫩煎) the meat in sunflower oil—no salt, no seasonings—didn’t know which was which. Both were flavorless, Ansky noted, but she would bet her reputation that sample A was the real thing. It had a richer, more “chickeny” taste.

The tasting was hosted by a meat-tech startup SuperMeat at its in-house restaurant, The Chicken. Ever since 2013, when the first lab-grown hamburger was presented to the public with a $330,000 price tag, alternative-meat companies have been inching closer to a product that is just as tasty and nearly as affordable as the real thing, but without the climate impacts. One new study found high-income countries could cut agricultural emissions (排放物) by almost two-thirds by moving away from animal-based foods.

But one question remains: Would consumers be able to tell the difference? SuperMeat decided to put its product to the test without the deep frying and sauces that are usually used to mask a lack of flavor. Sample B had less flavor, so Ansky reasoned that it had to be the one grown in a lab. She was so convinced of her decision that when SuperMeat founder Ido Savir announced that it was in fact A that was lab-grown, she corrected him. “No,” she said. “A is the real chicken.”

A day later, I spoke to Ansky about the tasting. “It’s one of the only times in my life that I’m really happy that I was wrong,” she admitted.

Ski resorts in northern China are seeing their business skyrocket, as winter sports     1     （get）more popular in China supported by a multi—year national campaign ahead of the 2022 Winter Olympics.

“When we opened a few years ago, there was no one here     2     （ski）; even during the Chinese New Year, there were only around 300 people. Now, we have over 3, 000 each day,” Luo Li, chairman of Zhangjiakou Wanlong Sports and Tourism Co. in the ski resort city of Zhangjiakou, told the Global Times.

Luo’s resort is not the only one in Zhangjiakou     3     has more business. A recent report from the city, which is also     4     host site for the Winter Olympics, said that the city     5     （expect）to see 2. 4 million people come to ski by 2022       6     the winter sports sector will drive 1 percent of the city’s total GDP by 2025.

Luo said that the increasing business has been supported by long—term investments by private businesses, as well as a national campaign to increase the     7     （popular）of winter sports ahead of the 2022 Winter Olympics in Beijing.

    8     （national）, as part of the preparation for the Winter Olympics and national exercise campaign, Chinese     9     （official）announced that measures would be taken     10     （encourage）as many as 300 million people to play winter sports.

9 . Before I lived in Pakistan, I was always with my grandfather. We were never ___________: I followed him wherever he went. He would never get ___________ with me when I wouldn't learn to do things. He always tried to cheer me up anytime I was in a bad ___________. I thought we would always live together.

However, on the morning of June 20, 2009, when I was 5, I went to ___________ grandfather, but he wouldn't open his eyes. I was   ___________, thinking he was just playing a game with me, but after trying for a while, I started getting _________. When my parents arrived, they explained solemnly (庄重地) to me his body didn’t work anymore. Slowly, I began to understand but couldn't face the truth. I stayed ___________ in my room, not speaking to anyone.

My parents had to call a psychologist (心理医生). Sonia was very kind, showing deep ___________ towards me. She said it was understandable to feel sad about death, but that didn't mean that I ___________ doing things that I used to do. Soon I started playing with my friends and talking to my family. My parents were pleased with my ____________. When I told them the pain I was going through, my eyes were filled with the ____________ instead of tears.

Dealing with a death of a family member is ____________, so it's hard to know what the right thing to do is. My grandfather's death made me realize that my life must move on, and that if I ____________ my feelings, it would be hard for me to overcome the pain. I'm now starting to forget the ____________ details of the time that he and I spent together, but I will never forget him and the ____________ he gave to me.