阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    A recent announcement by scientists that they have successfully cloned the first human embryo(胚胎) has caused much debate and has shocked many people around the world. On the one hand, some scientists point out that if you clone an embryo, you can produce valuable tissues(组织) and organs that could be used to save human lives. On the other hand, many people, including some scientists, disagree and fear that if mankind interferes with (干涉) nature in this way, they may be on their way to producing a real-life Frankenstein's monster.

Cloning is producing an exact copy of a plant or an animal using its cells. The first mammal to be cloned successfully from an adult cell was Dolly—the sheep. She was born in 1996 and died in early 2003, at a much younger age than normal. When she was born, many people were angry because they thought cloning would create more diseases in the animal world. However, in general the scientists were praised for their wonderful scientific breakthrough.

    The Scottish scientist who created Dolly, Ian Wilmut, is shocked that some scientists are now considering cloning human beings. Although he researches cloning, he has never thought of creating copies of humans. Instead, he thinks the scientists should concentrate on creating new tissues and organs that could eventually be used to cure diseases like cancer. However, some people consider that cloning human embryos with the intention of destroying them shows no respect for human lives.

    While cloning human embryos is illegal in many countries, some scientists are already pushing ahead with the research so as to deliver a cloned human baby. Severino Antinori, an Italian doctor, is one of the leaders in this field of research. He has declared that he wants to be the first to clone a human being.

In China, scientists have focused their efforts on cloning animals, as well as stem cells to be used in medical research. China has succeeded in producing clones of cows and goats, and continues to research ways in which cloning can benefit mankind.

    It's OK to say you've never heard of grime (伦敦地下音乐) - unless you're from the UK. That's because this music type was invented in the UK in the early 2000s.

    To someone who's not familiar with underground music culture, it's easy to get confused between hip-hop and grime since they are both noisy. And many people didn't bother to tell them apart，until earlier this month when grime stars like Stormzy and J Hus led this year's Mobo – “music of black origin”, an award in the UK. Just like UK electronic music and hip-hop, from which grime drew influence, it mostly reflects the thoughts of young people. But different from hip-hop, grime singers sing in dialects with strong accents, giving a special flavor to their songs.

    Lady Leshurr，known as the “Grime Queen”, said that she once tried to hide her accent, as she didn't want people to judge her. But one day, she realized that she didn't need to change herself just to please others. And there's no doubt that this is the soul of grime music: be yourself.

    Grime has challenged modem music in its production beauty and its expressions. Also different from the hip-hop culture, which usually focuses on being rich, grime singers pay more attention to social phenomena like those who suffer from disasters and the gap between the rich and poor.

    Although still quite a young music type, grime seems to be getting loved by more and more people. In 2016, the English grime artist Skepta won the Mercury Prize with his album Konnichiwa, beating big names like David Bowie and Radiohead.

    However, no matter whether grime is one day accepted widely or not, one thing is for sure: in grime, singers always stay true to themselves.

    Over the years, Brian Wansink, director of the Food and Brand Lab at Cornell University, has studied such things as how far Americans typically drive to buy food, how many times we refill our plates at all-you-can-eat buffets and how we organize our kitchens. In the mid-2000s he famously coined the phrase "mindless eating"(and wrote a book by that name) to focus attention on all the bad dietary decisions we make without really thinking about them.

    His new book, Slim by Design: Mindless Eating Solutions for Everyday Life, aims to change the design of restaurants, school lunchrooms, office cafeterias and homes so that the mindless choices we make will be more healthful ones. Some examples:

    Keep kitchen counters clear. No visible snack food, no bread, no nuts — not even breakfast cereal. In Wansink's research, "women who had even one box of breakfast cereal that was visible — anywhere in their kitchen — weighed 21 pounds more than their neighbor who didn't."

    Trick yourself into drinking less wine. "We tend to focus on the height of what we pour and not the width, so we pour 12 percent less wine into taller wineglasses than we pour into wider wineglasses." And the shape of the glass is not the only variable that affects how much we drink. Wansink writes: "Because red wine is easier to see than white wine, we pour 9 percent less red wine whenever we pour a glass."

    Wansink said his researchers also found that people ate less at restaurants when sat in well-lighted areas near windows and doors, than in darker areas or in the back. They ate less if they were offered a doggie bag, or to-go box, before they got their meals: apparently the idea of getting a "free" second meal outweighed the impulse (冲动) to clean their plates. Workers who frequently ate at their desks weighed 15.4 pounds less, on average, than those who didn't. Fruits and vegetables kept on the top shelf of the refrigerator were eaten at higher rates than those on lower shelves.

    The point, Wansink says, is to consider findings like those and change your environment or habits. Then you won't have to think about it: You'll just eat less.

Life is difficult.

    What do you think about life? Maybe most people say that life is difficult. But life is no longer difficult once we truly understand and accept it. Most people do not fully see this truth. Instead, they complain about their problems and difficulties as if life should be easy. It seems to them that their difficulties represent a special kind of suffering especially forced upon them or their families, their class, or even their nation.

    What makes life difficult is that the process of facing and solving problems is a painful one. Problems, depending on their nature, cause us sadness or loneliness or regret or anger or fear. These are uncomfortable feelings, often as painful as any kind of physical pain. And since life causes an endless series of problems, life is always difficult and is full of pain as well as joy.

    Yet, it is in this whole process of solving problems that life has its meaning.

    Problems are the serious test that tells success from failure. When we desire to encourage the growth of the human spirit, we encourage the human ability to solve problems, just as in school we set problems for our children to solve. It is through the pain of meeting and working out problems that we learn. As Benjamin Franklin said, “Those things that hurt instruct.” It is for this reason that wise people learn not to fear but to welcome the pain of problems.

    Are some people born clever, and others born stupid? Or is intelligence developed by our environment and our experience? Strangely enough, the answer to these questions is yes. To some extent our intelligence is given to us at birth, and no amount of education can make a genius out of a child born with low intelligence. On the other hand, a child who lives in a boring environment will develop his intelligence less than one who lives in rich and varied surroundings. While the limits of a person's intelligence are fixed at birth, whether or not he reaches those limits will depend on his environment. This view, now held by most experts, can be supported in a number of ways.

    It is easy to show that intelligence is to some extent something we are born with. The closer the blood relationship between two people, the closer they are likely to be in intelligence. Thus if we take two unrelated people at random(随机地) from population, it is likely that their degrees of intelligence will be completely different. If, on the other hand, we take two identical twins, they will very likely be as intelligent as each other. Relations like brothers and sisters, parents and children, usually have similar intelligence, and this clearly suggests that intelligence depends on birth.

    Imagine now that we take two identical twins and put them in different environments. We might send one, for example, to a university and the other to a factory where the work is boring. We would soon find differences in intelligence developing, and this indicates that environment as well as birth plays a part. This conclusion is also suggested by the fact that people who live in close contact with each other, but who are not related at all are likely to have similar degrees of intelligence.

I didn't go to Santiago,Chile to look for friendship.In fact,Chile was not even on my wish list.

A mid-life crisis woman,I got a chance to study abroad.I only wanted to learn about global business,taste South American  cuisine,and  check"study  abroad"off my  wish  list.

On the fifth day,I joined a group for a neighborhood work project aided by the anti-poverty(扶贫)organization. Our tasks were to build a water tower and paint the community center.Upon arrival,I couldn't believe my eyes.It was like a scene out of a horrible film.That moment redefined poverty for me because I had never seen such terrible living conditions.As advised,I showed no signs of the emotional battle going on inside me.

Just as I was about to start work on painting,a request came through for a few volunteers to help Nadia,a local resident who volunteered to cook for us.I raised my hand to help because I wanted to spend time with the people of the neighborhood despite my shortage of Spanish speaking skills.  Nadia had a sincere smile but not overly friendly.Even without speaking each other's language,we started to learn about one another.We chatted about our children,our upbringing,shared pictures of our family,struggled to instruct each other to communicate in the other's language,and laughed many times.

After we fed everybody and the dishes were washed,my day was over.But I found myself hesitant to leave.It was as if I had known her my entire life.I had not predicted the unselfishness of heart I would encounter,and it was moving.

As we were waiting for the car to pick us up,Nadia showed me her plants that are well-maintained.I could see that despite the hard conditions she was passionate about life.She made me long to be a stronger person.She showed me that poverty was external,but happiness was internal.I was seeking to give 100 percent for a well-intentioned cause,but I left receiving 200 percent from her.