3.　　 Which of the following is not mentioned in the passage?

A.Names of negative calorie foods.　　　　

B.What negative calorie foods are.

C.The effect of negative calorie foods.　　　　　

D.How negative calorie foods work.

Passage 8

Burning the midnight oil before an exam or interview has an opposite effect according to a research which found that sleep is necessary for memories to be "downloaded" into the brain.

"A good night’s sleep within 30 hours of trying to remember a new task is a necessary condition of having good recall (回忆) in the weeks ahead," scientists have found.

"We think that getting that first night’s sleep starts the process of memory consolidation (加强)," said Robert Stickgold, a sleep researcher at Harvard Medical School who conducted the latest study.

"It seems that memories are normally washed out of the brain unless some process nails them down. I feel uncertain that sleep is one of those things that do the nailing down," Professor Stickgold said.

Professor Stickgold’s team trained the 24 people to tell the direction of three diagonal bars(斜线) shown for a sixtieth of a second on a computer screen full of horizontal stripes(水平线条).

Half the subjects were kept awake that night, while the others slept. Both groups were allowed to sleep for the second and third nights to make up for any differences in tiredness between the volunteers(志愿者).

Those who slept the first night were much better at remembering the task while the second group showed no improvement in spite of enjoying two nights of catch?up sleep.

A further study by scientists at the Medical University at Lubeck in Germany showed that memories are laid down in two stages during the night. The first is during the deep, so?called "slow wave" sleep, which usually takes place in the first half of the night. The second, and less important stage happens during the periods of dreaming or "rapid eye movement (REM)". When people don’t sleep well in the first half of the night, their memory consolidation is almost the same as having no sleep at all.

2.　　 How can you get negative calories, according to the passage?

A.　　　 Eat less food than necessary.

B.　　　 Eat foods that contain more calories than the calories it takes to digest.

C.　　　 Eat foods that require more calories to digest than the calories you get from the foods.

D.　　　 Eat less food and exercise more.

1.　　 The author of this passage suggests that if you want to lose weight you should_______.

A.eat foods with less calories　　　　

B.eat foods with negative calories

C.starve more　　 　　　　　　　　

D.eat foods with low calories and delicious taste

5. It can be inferred from the passage that the author _______.

　 A) is in favor of prohibiting passengers' use of electronic devices completely

　 B) has overestimated the danger of electromagnetic interference

　 C) hasn't formed his own opinion on this problem

　 D) regards it as unreasonable to exercise a total ban during flight

Passage 7

Negative calories? You’ve got to be kidding me.

Is this possible? Can a food actually not only have no calories, but even have negative calories? Could you literally eat your way to fat loss?Yes. Although all foods carry some calories, the overall effect of certain foods in our body is that of "Negative calories".

Negative calorie foods are foods that use more calories to digest than the calories the foods actually contain.

Calories from these foods are much harder for the body to break down and process. In other words, the body has to work harder in order to extract calories from these foods. This gives these foods a natural fat?burning advantage.

For example, a piece of pie consisting of 350 calories may only require 100 calories to be digested, thus a net gain of 250 calories will be added to your body fat.

But, if you eat 65 calories of a food that requires 150 calories to digest, then you’ve burnt an additional 50 calories simply by eating that food.

There are a large number of foods that combine low calories, delicious taste, and excellent negative calorie properties. To lose weight, you should not starve. Instead,eat a lot of negative calorie foods to lose that extra fat and become slim naturally.

4. Why is it difficult to predict the possible effects of electromagnetic fields on an airplane's computers?

　 A) Because it is extremely dangerous to conduct such research on an airplane.

　 B) Because it remains a mystery what wavelengths are liable to be interfered with.

　 C) Because research scientists have not been able to produce the same effects in labs.

　 D) Because experts lack adequate equipment to do such research.

3. Few airlines want to impose a total ban on their passengers using electronic devices because　 ______.

　 A) they don't believe there is such a danger as radio interference

　 B) the harmful effect of electromagnetic interference is yet to be proved

　 C) most passengers refuse to take a plane which bans the use of radio and cassette players

　 D) they have other effective safety measures to fall back on

2. What is said about the over 100 aircraft incidents in the past 15 years?

　 A) They may have been caused by the damage to the radio systems.

　 B) They may have taken place during take-off and landing.

　 C) They were proved to have been caused by the passengers' portable computers.

　 D) They were suspected to have resulted from electromagnetic interference.

1. The passage is mainly about _______.

　 A) a new regulation for all airlines 　　B) the defects of electronic devices

　 C) a possible cause of aircraft crashes 　D) effective safety measures for air flight

5. What does the author say about straight，horizontal bars painted across roads?

　 A) They are falling out of use in the United States.

　 B) They tend to be ignored by drivers in a short period of time.

　 　C) They are applicable only on broad roads.

　 D) They cannot be applied successfully to traffic circles.

Passage 6

　　 The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable computer in business class. In the last 15 years, pilots have reported well over 100 incidents that could have been caused by electromagnetic interference. The source of this interference remains unconfirmed, but increasingly, experts are pointing the blame at portable electronic devices such as portable computers, radio and cassette players and mobile telephones.

　　 RTCA, an organization which advises the aviation (航空) industry, has recommended that all airlines ban (禁止) such devices from being used during "critical" stages of flight, particularly take-off and landing. Some experts have gone further, calling for a total ban during all flights. Currently, rules on using these devices are left up to individual airlines. And although some airlines prohibit passengers from using such equipment during take-off and landing, most are reluctant to enforce a total ban, given that many passengers want to work during flights.

　　 The difficulty is predicting how electromagnetic fields might affect an aircraft's computers. Experts know that portable devices emit radiation which affects those wavelengths which aircraft use for navigation and communication. But, because they have not been able to reproduce these effects in a laboratory, they have no way of knowing whether the interference might be dangerous or not.

　　 The fact that aircraft may be vulnerable (易受损的) to interference raises the risk that terrorists may use radio system in order to damage navigation equipment. As worrying, though, is the passenger who can't hear the instructions to turn off his radio because the music's too loud.　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

4. The American Association Foundation for Traffic Safety plans to __________.

　 A) try out the Japanese method in certain areas

　 B) change the road signs across the country

　 C) replace straight，horizontal bars with chevrons

　 D) repeat the Japanese road patterns