1 . Fortunately, the days of being spread on thick baby oil and lying in the sun to get you skin yellowish-brown—or more likely burnt—are long over. Many sunscreens work by filtering (过滤) the sun’s ultraviolet (UV) rays to keep them from reaching skin cells and causing the DNA damage that can lead to wrinkles and skin cancer. But in recent years, the safety of some of those filtering chemical ingredients, particularly oxybenzone (氧苯铜), has been in question.

A 2019 study published in JAMA found evidence that oxybenzone is absorbed into the bloodstream, leading to concerns about whether it might affect functions of our body. Oxybenzone has also been detected in breast milk for newborn babies. Because of concerns about higher intake in children, doctors from the American Academy of Pediatrics advise against sunscreen with oxybenzone for kids.

The Environmental Working Group, an activist organization that monitors chemical safety, has called for a ban, but the U.S. Food and Drug Administration considers sunscreens with oxybenzone safe. “It’s uncertain,” says Deborah S. Sarnoff, president of the U.S. Skin Cancer Foundation. “Just because you’re absorbing the chemical doesn’t mean it’s dangerous.” Further study is required.

But oxybenzone is a risk to coral reefs. Hawaii and the U.S. Virgin Islands have banned the sale of sunscreens with oxybenzone. In a 2022 study published in Science, researchers found that some certain sea plants, when exposed to sunlight, turn oxybenzone into energy or something needed in a way that damages and kills corals.

Some companies have been trying to stop using oxybenzone gradually in stages, and many big brands offer oxybenzone-free options. For anyone who is pregnant or breastfeeding, or simply looking to avoid these chemical filters, Dr. Sarnoff recommends mineral sunscreens, which contain mainly physical barriers.

3 . In our information-driven society, shaping our worldview through the media is similar to forming an opinion about someone solely based on a picture of their foot. While the media might not deliberately deceive us, it often fails to provide a comprehensive view of reality.

Consequently, the question arises: Where, then, shall we get our information from if not from the media? Who can we trust? How about experts- people who devote their working lives to understanding their chosen slice of the world? However, even experts can fall prey to the allure of oversimplification, leading to the “single perspective instinct” that hampers (阻碍) our ability to grasp the intricacies (错综复杂) of the world.

Simple ideas can be appealing because they offer a sense of understanding and certainty. And it is easy to take off down a slippery slope, from one attention-grabbing simple idea to a feeling that this idea beautifully explains, or is the beautiful solution for, lots of other things. The world becomes simple that way.

Yet, when we embrace a singular cause or solution for all problems, we risk oversimplifying complex issues. For instance, championing the concept of equality may lead us to view all problems through the lens of inequality and see resource distribution as the sole panacea. However, such rigidity prevents us from seeing the multidimensional nature of challenges and hinders true comprehension of reality. This “single perspective instinct” ultimately clouds our judgment and restricts our capacity to tackle complex issues effectively. Being always in favor of or always against any particular idea makes you blind to information that doesn’t fit your perspective. This is usually a bad approach if you would like to understand reality.

Instead, constantly test your favorite ideas for weaknesses. Be humble about the extent of your expertise. Be curious about new information that doesn’t fit, and information from other fields. And rather than talking only to people who agree with you, or collecting examples that fit your ideas, consult people who contradict you, disagree with you, and put forward different ideas as a great resource for understanding the world. If this means you don’t have time to form so may opinions, so what?

Wouldn’t you rather have few opinions that are right than many that are wrong?

6 . It is an honor for me to deliver this speech and on behalf of the graduating students, welcome you to this special ceremony 2020.

This is a unique moment. We are stepping up to another phase of our lives at a time of great hardship and global difficulties. Hope this ceremony will help erase sad memories, refresh beautiful ones and add more splendid memories into our lives.

I was born in the middle of war, which caused my family to move to Serbia for three years. When the war ended, we returned to Bosnia. My mother, who is and will ever be my heroine, was the only figure who guided me, provided for me and kept me on the right track, in the hope for a better life. I owed her so much as she is responsible for huge part of my success. I will always remember her teachings “to complain less and always find solutions at the price of whatever it takes” ， which brought me to China, an ancient land of new hopes.

During the COVID-19 outbreak, I got the best opportunity to understand China. I saw millions of people united with one goal-to win the battle against this epidemic. I have never seen such a collective dedication from a nation, turning things for the better by sacrificing personal convenience on a grand scale. China's governance and health care system proves to be one of the most efficient in the world. With a population of 1.4 billion, China not only has successfully controlled the transmission of the corona-virus but also assisted many other countries across the globe.

Everyone has a role to play in the battle against the virus. In Tsinghua, I played a tiny but necessary role: Staying on campus, studying online, cooperating during temperature checks and respecting social distancing measures. The rules set by the university and Chinese government had everyone's health and safety as first priority. This made me feel safe and confident that China was on the right track towards victory. Throughout this time, despite the immense challenges, Tsinghua has facilitated many online conferences, which helped me nurture more skills in my field of study.

Friends, we are now graduating from one of the world’s most prestigious universities. Tsinghua has been like a mother to us over the past months and years, guiding and nurturing us along the way, providing us with great vision and placing on us high expectations. So what comes next? Actions speak louder than words. Let us accept new challenges, think beyond our limits and keep in mind the ethics of life.

Let's undertake everything we can for the sake of unity, humanity and the international community. Let's work together for a more promising future and prosperous world.

7 . I was given a voice. That’s what people said about me I trained my voice, because it would be a shame to waste such a gift. I pictured this voice as a greenhouse plant and made sure it was provided with the right temperature, the right amount of water. I relieved its fears. I told it not to tremble. I nursed it, I trained it, and I watched it climb up inside my neck

My voice bloomed. People said I had grown into my voice. Invitations to perform flooded over us. All the best places wanted us. I was sought after, or rather my voice was. We went everywhere together and gave performances. Bouquets （花束）were thrown to it. Money was presented to it. Men fell on their knees before it. Applause flew around it.

Then my voice began to shrivel. People said my voice would bloom only for a certain term: finally it would drop off and gone with it would be all the fame and wealth. I have noticed it so far. Fear has entered me since my voice has used up most of my life. I’ve given it all my love. But my voice is still as greedy as ever. It wants more: more and more, more of everything it has had so far.

Now it’s evening: the bright lights come on, and excitement quickens in the streets. We sit in this hotel room. Soon it will be time for us to go out. We have to attend a grand occasion. The two of us chained together as always. I have to put on its favourite dress, its favourite necklace and wind a fur around it. Then I have to go out: shining like ice: my voice attached to my throat like an invisible vampire （吸血鬼）.

8 . Hardware in general, and smartphones in particular, have become a huge environmental and health problem in the Global South’s landfill sites(垃圾填埋场).

Electronic waste (e-waste) currently takes up 5 percent of all global waste, and it is set to increase rapidly as more of us own more than one smartphone, laptop and power bank. They end up in places like Agbogbloshie on the outskirts of Ghana’s capital, Accra. It is the biggest e-waste dump in the world, where 10,000 informal workers walk through tons of abandoned goods as part of an informal recycling process. They risk their health searching for the precious metals that are found in abandoned smartphones.

But Agbogbloshie legally should not exist. The Basel Convention, a 1989 treaty, aims to prevent developed nations from unauthorized dumping of e-waste in less developed countries. The e-waste industry, however, circumvents regulation by exporting e-waste labelled as “secondhand goods” to poor countries like Ghana, knowing full well that it is heading for a landfill site.

A recent report found Agbogbloshie contained some of the most dangerous chemicals. This is not surprising: smart phones contain chemicals like mercury(水银), lead and even arsenic(砷). Reportedly, one egg from a free-range chicken in Agbogbloshie contained a certain chemical which can cause cancer and damage the immune system at a level that’s about 220 times greater than a limit set by the European Food Safety Authority (EFSA). Most worryingly, these poisonous chemicals are free to pollute the broader soil and water system. This should concern us all, since some of Ghana’s top exports are cocoa and nuts.

Some governments have started to take responsibility for their consumers’ waste. For example, Germany has started a project that includes a sustainable recycling system at Agbogbloshie, along with a health clinic for workers. However, governments cannot solve the problem alone, as there is an almost limitless consumer demand for hardware, especially when governments’ green policies are focused on issues like climate change.

Only the manufacturers can fix this. A more economically sustainable and politically possible solution is through encouraging hardware manufacturers to make the repair, reuse and recycling of hardware profitable, or at least cost-neutral.

9 . The expression, "everybody's doing it," is very much at the center of the concept of peer pressure. It is a social influence applied on an individual in order to get that person to act or believe in a(n) ___ way as a larger group. This influence can be negative or positive, and can exist in both large and small groups.

People are social creatures by nature, and so it is hardly ___that some part of their self-respect comes from the approval of others. This instinct explains why the approval of peers, and the fear of ____, is such a powerful force in many people's lives. This instinct drives people to dress one way at home and another way at work, or to answer a simple “fine" when a stranger asks "how are you?" even if it is not necessarily true. There is a(n) _____aspect to this: it helps society to function efficiently, and encourages a general level of self-discipline that ___day-to-day interaction between people.

For certain individuals, seeking social acceptance is so important that it becomes a(n) ___: in order to satisfy the desire, they may go so far as to ___their sense of right and wrong. Teens and young adults may feel forced to use drugs, or join gangs that ____criminal behavior. Mature adults may sometimes feel ___ to cover up illegal activity at the company where they work, or end up in debt because they are unable to hold back the desire to buy a house or car that they can't afford in an effort to ___ the peers.

However, peer pressure is not always negative. A student whose friends are good at ___may be urged to work harder and get good grades. Players on a sports team may feel driven to play harder in order to help the team win. This type of ___can also get a friend off drugs, or to help an adult take up a good habit or drop a bad one.

Although peer pressure is sometimes quite obvious, it can also be so ___that a person may not even notice that it is affecting his or her behavior. For this reason, when making important decisions, simply going with a(n) ___is risky. Instead, people should seriously consider why they feel drawn to taking a particular action, and whether the real ____ is simply that everyone else is doing the same thing.

10 . What makes a human being? Is it our thoughts? Our emotions? Our behavior?

All of these things make us who we are, but at the center of the matter is the genome(基因组) the genes inside our bodies that may determine everything from our hair color to our intelligence. But if we could change our genome, what would it mean to us?

In an online video posted on Nov. 26, He Jiankui, a biological researcher from Southern University of Science and Technology in China, said that he had helped to make the world’s first genetically edited babies.

These are twin girls, born in November, with genes edited in an attempt to help them resist possible future infection with the AIDS virus.

He said that he chose to do this because HIV infections are a big problem in China. “I feel such a strong responsibility that it’s not just to make a first, but also to set an example,” He told the Associated Press(AP).

The announcement has caused an international storm.

Some believe that success will benefit the families of HIV patients. Given that HIV is “a major and growing public health threat,” attempted gene editing for HIV is “justifiable(无可非议的),” Harvard Medical School genetics professor George Church told AP.

However, others think that since gene editing technology is still premature, it is unsafe to attempt it.

“Gene editing itself is experimental and is still associated with unexpected mutations(突变), capable of causing genetic problems early and later in life, including the development of cancer.” Julian Savulescu, a specialist in ethics(伦理学) at the University of Oxford, told BBC News.

Others fear that this could open the door to using gene editing technology to make designer babies. It might give the parents the options to choose everything from their baby’s eye color to intelligence.

“You could find wealthy parents buying the latest ‘upgrades’(升级) for their children, leading to even greater inequality than we already live with,” Marcy Darnovsky, director of the San Francisco Center for Genetics, told BBC News.

However, Merlin Crossley, a biologist at the University of New South Wales, Australia, believes that’s a long way off . According to him, many genes produce qualities like height and intelligence—not to mention environmental influences.

And he believes the technology will be better controlled in the future.

“It’s hard to get genies(妖怪) back into bottles... but I’m optimistic that this technology, which I think of as ‘genetic surgery’, could be regulated quite effectively in the future,” Crossley told BBC News.