1 . Antioxidants (抗氧化剂) are found naturally inn plants like blueberries, blackberries, and red cabbage. Scientists believe antioxidants may help prevent heart disease and help fight against diseases like diabetes. But tomatoes naturally only have a small amount of antioxidants in them.
British scientist Cathie Martin wanted to see if she could create tomatoes with lots of antioxidants by changing the DNA of a tomato plant.
A plant developed from specially created DNA is known as a GMO, or “genetically modified organism”. For hundreds of years, farmers have created new kinds of plants by mixing existing plants together using natural methods. GMO plants are different because the plants’ DNA has been changed by scientists. Scientists who do this usually think they’re improving the plants in some way.
After working on developing purple tomatoes for years, Dr. Martin’s experiment worked. Soon her plants were producing small purple tomatoes. Though the color is unusual, what’s really special about the tomatoes is that they have very high levels of antioxidants. Even better, the tomatoes remained fresh almost twice as long as normal tomatoes. Soon, Dr. Martin and other scientists created a company to promote the tomatoes.
The company tested its tomatoes on mice that were likely to get cancer. The mice who were fed the purple tomatoes lived about 30% longer than the mice who were fed normal tomatoes. Though that’s good news, experiments on mice don’t always predict what effects on humans will be like.
And GMO products weren’t popular with customers. Many people were scared by the idea that the foods weren’t “natural”. There are still questions about the effects of GMO crops on the environment and other plants, but most scientists agree that food from GMO crops is safe to eat.
On September 7, the government approved a GMO plant designed to target human health. Dr. Martin and her company plan to introduce the tomatoes at farmers’ markets across the US in 2023. They also hope to sell the seeds to people who want to grow their own.
1. What is the function of paragraph 1?| A．To define a concept. |
| B．To bring in the topic of the text. |
| C．To add background information. |
| D．To introduce the benefits of antioxidants. |
| A．Their medical value. | B．Their delicious flavor. |
| C．Their proper size. | D．Their pleasant color. |
| A．They are expensive to buy. |
| B．They are intended for animals. |
| C．They are thought to be harmful. |
| D．Their appearance isn’t appealing. |
| A．Opposed. | B．Unclear. | C．Positive. | D．Concemed. |
2 . Imagine you are on a cold mountain with steep rocks around. As you climb higher, the air gets thinner and the sun’s rays stronger. Just before you reach the snowline, you find what you came for—a small white flower, the edelweiss, which only grows in alpine areas.
Plants face many challenges living in alpine areas, and only 200 kinds of plants can grow there. Plants rely on oxygen, water, and sunlight to make their own food through the process of photosynthesis. The alpine means less CO2, which makes the process more difficult. It also brings plants closer to the sun. The sunlight is so strong that it can burn a plant’s leaves. There is little water here, so the soil is dry and rocky. You also won’t find high trees because the cold wind would blow them over！
Alpine plants have advantages that help them survive the bad conditions. Like all alpine plants, the edelweiss stays close to the ground to avoid the wind. The cold water is deep underground, so the edelweiss grows very deep roots. Its leaves have a thick covering, which protects the plant from the wind and the sun’s bright rays. All these special characteristics help it grow, but very slowly.
The edelweiss can live in the conditions, but humans can’t. Climbing in the high and cold mountains is dangerous and difficult. This is why the edelweiss became such a special flower. Long ago, a young man would pick an edelweiss flower to prove his love to a girl, although it was risky. Many men died while trying. Getting the flower proved that the man was physically strong, brave, and devoted.
Alpine plants can’t spread seeds, so it’s difficult for new plants to grow. Once all the edelweiss flowers are gone in an area, they will not regroup. Governments help protect the edelweiss because it is considered an endangered plant.
1. The first two paragraphs mainly describe ________ .| A．the process of photosynthesis | B．the appearance of the edelweiss |
| C．the growing environment of the edelweiss | D．the challenge of mountain climbing |
| A．it grows high and strong | B．it can get more sunlight |
| C．its leaves’ covering is thin | D．its deep roots can get water |
| A．It is planted in large quantities. | B．It is a symbol of bravery. |
| C．It is a shade loving plant. | D．It spreads its seeds by wind. |
| A．To introduce a special flower. | B．To compare different alpine plants. |
| C．To warn people not to pick flowers. | D．To encourage people to protect plants. |
3 . High on the top of California's White Mountains, the hard conditions make it difficult for life to take root. But for a certain type of tree — and for those who have travelled here to study it — this place is a perfect place.
These bristlecone pines are the oldest individual trees in the world. Researchers like Andy Bunn have come to learn from the ancients. "It's remarkable to sit here and have your hand on one of these trees and know that it was growing when the Pyramids were built." Bunn added.
"By studying samples (样本) from the trunks, it's possible to discover their hidden history. Each annual tree ring is like a time capsule of the environment for that year from which it was formed," said Matt Salzer, a scientist at the University of Arizona's Laboratory of Tree Ring Research. "And it contains many different types of information — chemical information, the information on growth, and climate information."
"If you're trying to look at people in the past through time, tree rings give you a way to do it in a way that makes sense in a human life," said University of Arizona Professor Charlotte Pearson. She first became fascinated with the bristlecones after reading about an ancient volcanic eruption on the Greek island of Santorini. "It blew my mind that trees on the other side of the world could possibly be used to date this thing within a single year," she said excitedly.
The oldest known living bristlecone is estimated to be over 4, 800 years old. For Bunn, the climate record written in the rings offers guidance for how we might think about what's happening in the present as we plan for the future. "What we're seeing increasingly is that a lot of the climate events that we are experiencing and living through right now have no example in the paleoclimate (古气候) record," he said. “So, we really are moving into unknown field."
1. Why does Bunn mention the Pyramids in Paragraph 2?| A．To state the trees' age is very old. | B．To prove his discovery is important. |
| C．To attract readers' attention. | D．To stress the hard living condition of the trees. |
| A．The result of the research. | B．The process of the research. |
| C．The method of the research. | D．The significance of the research. |
| A．It confused me. | B．It surprised me. |
| C．It defeated me. | D．It disappointed me. |
| A．Paleoclimate record is hard to find. |
| B．There are lots of unknown things about pines. |
| C．Studying the tree rings is important for climate research. |
| D．There were frequent occurrences of the extreme climate events. |
