1 . Supermarket shelves are filled with plant-based alternatives (可代替品) to cow milk, including soy, nut, and coconut milk. These products are popular with consumers who cannot drink cows’ milk for health reasons, as well as with those concerned about animal welfare and environmental sustainability. While the dairy-free (非乳制的) options work well with cereal or in coffee, they fail miserably when it comes to making milk-based products like cheese or yogurt. However, these shortcomings may soon be a thing of the past, thanks to a new company in California, which has figured out how to create animal-free milk in a laboratory!
Perumal Gandhi and Ryan Pandya founded the company in 2014 after becoming increasingly annoyed with the lack of cows’ milk-free alternatives, particularly for cheese. For Gandhi, who stopped consuming animal products five years earlier due to environmental and animal welfare concerns, the motivation to create a better alternative stemmed from his love of cheesy pizza. Pandya was spurred (被激发) to take action after being forced to eat some “really bad” dairy-free cream cheese on his sandwich.
The two MIT biomedical engineering scientists decided to join forces to create a more realistic alternative to dairy-based products. In their university lab, the pair spent nine months first isolating (分离) cow DNA then inserting it into yeast (酵母). This genetic modification (改造) enabled the yeast to produce the necessary milk proteins. The final step of the process involved mixing the proteins with some plant nutrients and fats.
The dairy-free milk not only tastes like the real thing but is also healthier, has a longer shelf life and, most important of all, is Earth friendly. According to the company’s website, when compared to conventional (常规的) milk production, their process uses 65% less energy, creates 84% less greenhouse gas emissions (排放) and requires 91% less land and an amazing 98% less water! Best of all, since it contains real milk proteins, the product behaves like the cow-produced version, which means vegetarian (素食的) consumers will no longer have to deal with the unpleasant cheese on their sandwiches and pizzas.
The company plans to bring their creation to market later this year and their first product will most likely be cheese since there are already many good cows’ milk products available to consumers.
1. The underlined word “those” in paragraph 1 refers to _______.| A．actions | B．products | C．people | D．reasons |
| A．their deep concern for the environment |
| B．their worry that farm animals were poorly treated |
| C．the over-consumption of the dairy-based products |
| D．the poor taste of dairy-free cheese presently available |
| A．The dairy-free products cannot be stored for a long time. |
| B．Cow farming causes considerable environmental damage. |
| C．The new products will taste better than dairy-based ones. |
| D．The dairy-free milk will be more expensive than cow’s milk. |
| A．Healthier Cheese |
| B．New Milk Saves Planet |
| C．Making Milk without Cows |
| D．Fresher Milk, Better Future |
2 . In 2016, a team of Japanese scientists found bacteria capable of breaking down and “eating” one of the world’s most popular plastics-polyethylene terephthalate(PET). It was valued as a potential breakthrough at the time. But a new discovery came as a team of British scientists examined an enzyme(酶) produced by the Japanese bacteria to find out more about its structure. While operating the structure to better understand how it worked, they accidentally created the changed enzyme that’s even more efficient at breaking down plastic bottles.
The researchers are now working to further improve the enzyme so it can be used on an industrial scale. It’s possible that within the next few years there could be an industrially possible process for turning PET into other substances so it can be recycled.
The ability to scale up the process will be important. Plastic pollution is fast becoming one of the biggest environmental issues of our time. More than 1 million plastic bottles are bought around the world every minute. Most of these bottles are made from PET，which can take up to1000 years to biodegrade(生物降解), and many are left in the oceans. Over half of global PET waste is not collected for recycling and only 7 percent of bottles are recycled into new bottles.
Some scientists say the breakthrough, though promising, is nowhere near enough to solve our pollution crisis. These enzymes are not abundantly present in nature. So you would need to produce the enzyme first, then add it to the PET plastic to degrade it.”This is likely to be a slow process. If you have gone through the trouble of collecting the PET waste, then there are clearly far better ways to recycle it or burn it for energy,” said Wim, head of the Industrial Biotechnology Center. He suggested the use of commercially available biodegradable bioplastics would still be a better bet.
1. What unexpected discovery did the British scientists make?| A．An effective way to deal with plastic waste. |
| B．A potential solution in collecting PET waste. |
| C．The way to understand the structure of enzyme better. |
| D．The real value of the discovery by Japanese scientists. |
| A．The process to find the enzyme. |
| B．The process to make more plastics. |
| C．The process to reduce the PET waste. |
| D．The process to produce kind of new PET. |
| A．Large quantities of plastic bottles are used. |
| B．Ocean plastic waste is harder to biodegrade |
| C．Most of the PET waste is left without treatment. |
| D．Most of the plastic products are made from PET. |
| A．The enzyme does not exist in nature. |
| B．The enzyme has helped to solve the plastic problems. |
| C．Burning plastic waste for energy is now the best way to rid it. |
| D．We have a long way to go to use the enzyme to recycle PET waste. |
