A calorie is a unit of energy, not a measure of weight or nutrient density. The calories you see on nutrition labels，however，are actually kilocalories. The calories on food packaging always refer to kilocalories, even though it just says “calories”. One kilocalorie is the amount of energy required to heat 1 kilogram of water by 1 degree Celsius. Calories in our food all come from one of the three nutrients: fats, carbohydrates and proteins.

In 1990, the U. S. government passed the Nutrition Labeling and Education Act, which means that before any packaged food in the U. S. hits the shelves, food scientists have to measure its nutrients and calories. One way to do this is using a tool called bomb calorimeter（弹氧热卡计）. This tool directly measures the amount of energy that a food contains. To use this tool, scientists place the food in question in a sealed（密封的）container surrounded by water and heat it until the food is completely burned off. Scientists then record the rise in water temperature to determine the number of calories in the product.

Food scientists also rely on a calculation developed by the 19th-century U. S. chemist Wilbur Olin Atwater to indirectly estimate the number of calories in food products. Calorimeters don’t take into account that humans lose some calories through heat and feces（类便）. Atwater’s experiments found that proteins and carbohydrates each have about 4 calories per gram and fats have 9 calories per gram.

However, some experts say that the Atwater system is outdated and inaccurate. A 2012 study found that the energy content of certain foods, such as nuts, could not be accurately calculated by the Atwater system. Besides, it does not take into account the digestive process, but assumes the complete conversion of nutrients to energy.

【小题1】What can we learn about the unit of energy on nutrition labels?

A．It actually means calories.

B．It refers to kilocalories.

C．It reads kilograms.

D．It employs degrees.

【小题2】What should be done to measure the amount of calories according to the calorimeter?

A．Heat the food in an open container until the food is completely burned off.

B．Take the calories through heat and feces into consideration.

C．Learn the calculation developed by Wilbur Olin Atwater.

D．Calculate the amount of energy in food products directly.

【小题3】How many calories does a food containing 10 grams of proteins and 5 grams of fats have according to the Atwater system?

A．About 40.	B．About 45.
C．About 85.	D．About 130.

【小题4】What would be the best title for the text?

A．How Are Calorie Counts Calculated?

B．Where do Calories Come from?

C．Can Nutrients Be Converted to Energy Totally?

D．Nutrients and Calories Listed on a Food Label

语法填空
To find out whether such a"sixth sense" 【小题1】 (real) exists, Baker performed two experiments. In the first one, Baker 【小题2】(sit) behind unknowing people in public places and stared at the backs of their heads for 15 minutes. The subjects(实验对象)were eating, drinking, reading, studying, watching TV or working. And Baker made sure that the subjects could not tell that he was sitting behind them during those periods. Later, 【小题3】 he questioned the subjects, they said they had no sense 【小题4】 someone was staring at them.
In the second experiment, Baker told the subjects that they would be stared at 【小题5】 time to time from behind in a laboratory setting. The subjects had to write it down when they felt they were being stared at. Baker found that the subjects were not 【小题6】(good) at telling when they were stared at and when they weren't. Baker came to a 【小题7】(conclude) that people do not have the ability 【小题8】(sense) when they're being stared at. " If people doubt the results of these two experiments, I suggest they 【小题9】(repeat) the experiments and see it 【小题10】(they), " said Baker.

   Storing food is common in members of the crow family. A new study tested the birds outside for this naturally occurring behavior, which may have evolved（进化）specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to recover food. So the researchers tested whether the birds could store and recover a tool so they could use it to find their food after a gap of 17 hours — something we wouldn’t expect them to do naturally. But they were able to instantly select the tool out of a number of unnecessary items.

In another experiment, the researchers taught crows to select a token（礼品券）from a number of items so that they could then exchange it for food. Again, the birds then showed that they could plan for the future using this new behaviour. This is different from all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that chimpanzees select, transport and save appropriate tools for future needs.

These studies have shown that animals can plan for the future — but they leave an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviour.

But the new research provides the first evidence that animal species can plan for the future using behaviour that doesn’t typically occur in nature. This supports the view that at least some recognitive（认知的）abilities in animals don’t evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviour flexibly across problems in a similar way to humans. We need to study how flexible behaviour evolved. Then we might be able to see how crows’ ability to plan for the future fits in with their broader cognitive powers.

【小题1】What’s the new finding about some crows according to Paragraph 1?

A．They can store food.	B．They can use tools to recover food.
C．They can store and recover tools.	D．They can select and store food.

【小题2】What are crows trained by researchers to do when given a token?

A．Reject it casually.	B．Exchange it for food.
C．Save it as their food.	D．Build a nest with it.

【小题3】What can we infer about the studies that animals can plan for the future?

A．They are debatable.	B．They are disappointing.
C．They are logical.	D．They are convincing.

【小题4】What can be learned about flexible behaviour in animals?

A．It develops only with age.	B．It is unclear how it evolved.
C．No animals but crows benefit from it.	D．It helps plan for the future.

   A newly-published study has shown that loneliness can spread from one person to another，like a disease. Researchers used information from the Framingham Heart Study，which began in 1948. The Framingham Heart Study gathers information about physical and mental health，personal behavior and diet. At first，the study involved（使参加）about 5,000 people in the American state of Massachusetts. Now more than 12,000 individuals（个人）are taking part.

Information from the Framingham Heart Study showed earlier that happiness can spread from person to person. So can behavior like littering and the ability to stop smoking.

Psychologist John Cacioppo，at the University of Chicago，led the recent study. He and other researchers tried to show how often people felt lonely. They found that the feeling of loneliness spread through social groups.

Having a social connection with a lonely person increased the chances that another individual would feel lonely. In fact，a friend of a lonely person was 52% more likely to develop feelings of loneliness. A friend of that person was 25%more likely. The researchers said this shows that a person could indirectly be affected by someone’s loneliness.

The effect was the strongest among friends. Neighbors were the second most affected group. The effect was weaker on husbands and wives，and brothers and sisters. The researchers also found that loneliness spread more easily among women than men.

The New York Times newspaper reported that，on average，people experience feelings of loneliness about 48 days a year. It also found that every additional（额外的）friend can decrease loneliness by about five percent，or two and a half fewer lonely days.

Loneliness has been linked to health problems like depression（抑郁症）and sleeping difficulties. The researchers believe that knowing the causes of loneliness could help reduce it.

The study suggested that people can take steps to stop the spread of loneliness. They can do this by helping individuals they know who may be experiencing loneliness. The result can be helpful to the whole social group.

【小题1】As for the Framingham Heart Study we can learn that __________.

A．it was only conducted in 1948	B．it involves more than 12, 000 people
C．it was founded by John Cacioppo	D．it showed that any behavior could spread

【小题2】From the passage, we can learn that __________.

A．the behavior of littering doesn’t spread

B．a lonely person won’t have friends

C．everyone may be affected by others’ loneliness

D．lonely people don’t know the causes of their loneliness

【小题3】Which statement about the spread of loneliness is TRUE?

A．The spreading effect is the second strongest among friends.

B．No spreading effect is found on husbands and wives.

C．Women are more likely to be affected than men.

D．Brothers are more easily to be affected than neighbors.

【小题4】What is the main idea of the passage？

A．Action should be taken to help lonely people.	B．People feel lonely for many reasons.
C．Ways to fight against loneliness.	D．Lonely people can affect others.