1 . Unsolved Mysteries About the Planet Earth
◆Mystery 1: Where did all the water come from?
Water covers 70 percent of Earth’s surface and earns it the nickname “the blue planet”. And where did it come from? The most popular scientific theory states that the water came from several violent asteroids (小行星) filled with ice. Another suggests that the water actually has been around since Earth’s formation. However it happened, though, it’s certainly worked out well for Earth’s life forms.
◆Mystery 2 :What about all the oxygen?
Another thing is the planet’s oxygen. Tiny creatures released oxygen as a waste product, filling the atmosphere with it. After that, the level of oxygen in Earth’s atmosphere went wildly up and down until it finally calmed down around 540 million years ago. Since then, it’s remained at about the breathable level we experience today. But what caused it to be suddenly steady?
◆Mystery 3: What caused the Cambrian (寒武纪) Explosion?
The Cambrian Explosion refers to the explosion of complex life forms that occurred on Earth about 540 million years ago. Before then, life had consisted mostly of bacteria. But at the beginning of the Cambrian period, complex creatures began developing at a rate never seen before. Suddenly, life forms had brains, eyes, and bones. Most living creatures today can trace their blood back to the Cambrian period.
◆Mystery 4: Will we ever be able to predict earthquakes?
We still haven’t been able to come up with a way to accurately predict earthquakes. We can certainly try, but our current technology cannot predict them exactly. We know that earthquakes start when rocks crack underground and send earthquake waves toward the surface, but we haven’t figured out why that happens, or how to predict it.
1. Which of the following is true according to the text?| A．Earth is called the blue star because of water coverage. |
| B．The level of oxygen has been steady all the time. |
| C．Complex creatures had rapid development after the Cambrian period. |
| D．We know nothing about predicting earthquakes. |
| A．It is the oldest mystery of the four. |
| B．It will be solved in the near future. |
| C．It is the most difficult mystery to solve. |
| D．It is a matter that is of practical significance. |
| A．A diary. | B．A geography book. |
| C．A novel. | D．A magazine. |
2 . A new report from the U. K. says more than 1 in 5 teens there spend five hours or more per day on social media. And the heavier users of social media get to bed later and get poorer quality sleep. The new study was based on self-reported survey data from nearly 12,000 teenage participants in the U. K. Millennium Cohort Study.
Megan Moreno, a researcher at the University of Wisconsin Madison, says social media is too often described as either entirely good or bad, when the reality is more complicated(复杂的) for teens. Social media may have its problems, but it is the way that they stay in touch with each other,” she says.
Perhaps unsurprisingly, the study found a link between high social media usage and poor sleep patterns. Especially, teens who are heavier users of social media go to sleep later. And the researchers note late bedtime is linked with poorer academic and mental health consequences.
Holly Scott, a researcher at the University of Glasgow, isn’t sounding the alarm. She says, “It’s easy to look at the results of this and think, ‘We should just get teenagers to spend less time on social media. ‘ I think that’s an understandable response, but what I really encourage people to do is look beyond that. “ She says people should pay attention to the important emotional ,cognitive (认知的)and social factors when teenagers are using social media.
Scott stresses that the study is pointing to a connection between social media and poor sleep, but not necessarily explaining cause and effect.
“Certainly some teens do say they struggle to get away from social media at night - they might be worried about missing out on things, or affecting their friends by not answering messages -and they stay up late for that,” she says. “As for some of those young people, they have a naturally later body clock and they are passing their free time at night on social media until they’e ready to fall asleep.”
1. What’s the purpose of the new study in the U. K. ?| A．To find the benefits of using social media. |
| B．To know the effects of using social media. |
| C．To promote the development of social media. |
| D．To prove the growing popularity of social media. |
| A．Positive. | B．Doubtful. | C．Objective. | D．Confused. |
| A．Make better use of social media. |
| B．Spend less time on social media. |
| C．Study how social media influences teens. |
| D．Understand why teens like using social media. |
| A．Health. | B．Education. | C．Science. | D．Entertainment. |
3 . Courses & Curriculum of the College of Arts & Sciences in Cornell
The diversity of the courses you can take in the College of Arts & Sciences is extraordinary:
Academic Distribution Requirements
The College’s academic distribution requirements will include: effective writing; foreign language beyond the introductory level; imaginative and critical thinking.
To choose your courses for a semester, use the Class Roster. It shows the schedule of all classes offered in a particular term, along with class enrollment information and course details.
The Class Roster is updated frequently.
To plan your classes over your four years at Cornell, use the Courses of Study. It represents Cornell’s full catalog of courses and is published annually. It provides information on Cornell degree programs, requirements, policies and procedures.
If you need help, call 607-255-5004 for an appointment with an advising dean. Or contact a career counselor in the Arts & Sciences Career Development Center at 607-255-4166 to talk about your interests and how they can translate into a major and a future career.
A New Curriculum
On October 30, 2018, the College of Arts & Sciences faculty（教员）approved a new undergraduate curriculum to be carried out over the next two to three years. The new curriculum focuses on the theme of exploration and reaffirms the college’s commitment to a liberal arts and sciences education. Students who have questions about the new curriculum can view the approved proposal on the Course Designer app of Cornell.
Innovative Learning
If you’re one of the 3,000 students across the university taking biology or physics at the College, you may be part of an innovative（创新的）classroom project that uses active learning, a new model that is proving to be the quickest path to expert-level mastery.
Your education at Cornell will extend far beyond the classroom. You can join a faculty member’s research team on campus, conduct field study research in different states or spend a semester with Cornell in Washington D C. You could study abroad in one of more than 85 countries or develop your own research project through independent study. Give yourself the freedom to explore.
1. If you want to plan your courses over the long run, you can use the ______.| A．Class Roster | B．Courses of Study |
| C．Course Designer | D．Career Center |
| A．may study a new model |
| B．are on the quickest way to be experts |
| C．will get more freedom during research project |
| D．have advantages of studying outside the classroom |
| A．a college website | B．a science report |
| C．a travel magazine | D．an academic journal |
4 . Hybrid cars, also called hybrid electric vehicles （HEVs）, are cars that use more than one source of energy to run. They differ from the majority of cars on the road today in several ways. The main difference is that HEVs run on gasoline and electricity. An HEV car has a battery-powered motor as well as an engine that runs on gasoline.
A hybrid car is a bit more expensive to produce than a regular car even though its engine is smaller. The reason for the greater expense is that the engine is more complex. It has specialized mechanisms that allow it to operate using gasoline and electric power. It also contains a computer that works differently from those of regular cars. Even though it is more expensive to purchase, it costs less to own than gas-powered cars. When an HEV car is at a stoplight or going at a speed below 15 miles per hour, its special computer tells it to run just on electric power. When the computer senses that the car needs more power, it puts the gasoline engine back to work. The computer is constantly deciding whether the car will use electricity, gas, or a combination of the two.
Because the HEV has electric power to help it run, it uses much less fuel than most cars. In fact hybrid cars are the most fuel-efficient cars that exist today. They can get from 50 to 60 miles per gallon on average. The high mileage saves money for the car owner and conserves precious supplies of petroleum. Hybrid cars help the environment in other ways too. For example, when
the HEV is using electric power, it does not send out poisonous smoke that pollute the air.
Despite the differences between hybrid cars and regular cars, HEVs offer the same feel as regular cars. They handle the same way and speed up and stop in the same way too. HEVs, though, are generally smaller than gasoline-powered cars. Their rounded, aerodynamic frame helps add to their fuel efficiency but unfortunately does not add to the amount of space inside the vehicle.
1. Which statement best explains the characteristics of an HEV?| A．Safe and reliable. | B．Expensive but long-lasting. |
| C．Smaller engine, greater power. | D．High price, low carbon. |
| A．the engine | B．the battery |
| C．the computer | D．the driver |
| A．To save energy. | B．To provide better service. |
| C．To lower the expense of purchase. | D．To give the drivers a different feeling. |
| A．A health report. | B．A science magazine. |
| C．A vehicle advertisement. | D．A travel journal. |
