“Mobile phone killed my man,” screamed one headline last year. Also came claims that an unpublished study had found that mobile phones could cause memory loss. And a British newspaper devoted its front page to a picture supposedly showing how mobile phones could heat the brain.
For anyone who uses a mobile phone, these are worrying times. But speak to the scientists whose work is the focus of these scares and you hear a different story.
One of the oddest effects comes from the now famous “memory loss” study. Alan Preece and his colleagues at the University of Bristol placed a device that imitated the microwave radiation of mobile phones to the left ear of volunteers. The volunteers were good at recalling words and pictures they had been shown on a computer screen. Preece says he still can’t comment on the effects of using a mobile phone for years on end. But he rules out the suggestion that mobile phones have an immediate effect on our cognitive(认识的)abilities. “I’m pretty sure there is no effect on short-term memory,” he says.
Another expert, Tattersall, remarked that his latest findings have removed fears about memory loss. One result, for instance, suggests that nerve cell synapses(神经元突触) exposed to microwaves become more — rather than less — receptive to undergoing changes linked to memory formation.
An even happier outcome would be that microwaves turned out to be good for you. It sounds crazy, but a couple of years ago a team led by William Adey at the Veterans Affairs Medical Center in California found that mice exposed to microwaves for two hours a day were less likely to develop brain tumours when given a cancer-causing chemical.
“If it doesn’t certainly cause cancer in animals and cells, then it probably isn’t going to cause cancer in humans,” says William. And while there’s still no absolute evidence that mobile phone use does damage your memories or give you cancer, the conclusion is: don’t be afraid. Mobile phone users are worried because ______.
A.they are not sure whether mobile phones can cause memory loss |
B.it’s said that mobile phones have a lot of side effects |
C.one headline reported “Mobile phone killed my man” |
D.a British newspaper s![]() |
According to this passage, we can know that _____.
A.the mobile phone is a most wonderful invention |
B.there’s no need to worry about the radiation from mobile phones |
C.something must be done to stop people using mobile phones |
D.mobile phone companies shouldn’t cheat customers |
What would be the best title for this passage? ______.
A.New Mobile Phones. | B.Special Mobile Phones. |
C.New Special Investigation: Mobile Phones. | D.New Investigation. |
Everywhere man is altering the balance of nature.He is facilitating the spread of plants and animals into new regions, sometimes deliberately, sometimes unconsciously.He is covering huge areas with new kinds of plants, or with houses, factories, slag-heaps and other products of his civilization.He exterminates some species on a large scale, but favors the multiplication of others.In brief, he has done more in five thousand years to alter the biological aspect of the planet than has nature in five million.
Many of these changes which he has brought about have had unforeseen consequences.Who would have thought that the throwing away of a piece of Canadian waterweed would have caused half the waterways of Britain to be blocked for a decade, or that the provision of pot cacti for lonely settlers’ wives would have led to Eastern Australian being overrun with forests of Prickly Pear? Who would have prophesied that the cutting down of forests on the Adriatic coasts, or in parts of Central Africa, could have reduced the land to a semi desert, with the very soil washed away from the bare rock? Who would have thought that improved communications would have changed history by the spreading of disease-sleeping sickness into East Africa, measles into Oceania, very possibly malaria into ancient Greece?
These are spectacular examples; but examples on a smaller scale are everywhere to be found.We make a nature sanctuary for rare birds, prescribing absolute security for all species; and we may find that some common and hardy kind of bird multiplies beyond measure and ousts the rare kinds in which we were particularly interested.We see, owing to some little change brought about by civilization, the starling spread over the English country-side in hordes.We improve the yielding capacities of our cattle; and find that now they exhaust the pastures which sufficed for less exigent stock.The following examples except _______________ reflect man altering the balance of nature.
A.man is covering huge areas with new kinds of plants |
B.man is fa![]() |
C.man is killing some species on a large scale |
D.man is getting to know the importance of keeping the balance of nature. |
What had a piece of Canadian waterweed cause?
A.Eastern Australian was overrun with forests. |
B.Half the waterways of Britain blocked for a decade. |
C.In parts of central Africa, the land reduced to a semi desert. |
D.Disease-sleeping has been caused. |
What have spread diseases?
A.Disease-sleeping sickness. | B.Measles. |
C.Improved communications. | D.Malaria. |
We make a nature sanctuary for rare birds but _______________.
A.some common and hardy kind of bird multiplies |
B.rare kinds multiply |
C.all bird multiply |
D.no bird multiply |
The main idea of the passage is ______________.
A.that man is deliberately destroying the balance of nature |
B.that man has foreseen the consequences of altering the balance old nature |
C.that improved communications have changed history |
D.that man is altering the balance of nature |
Microwaves may be great at warming up food, but what about warming people?
Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture. And despite popular ideas about microwaves, this techniqu
e would be safe, according to Charles R. Burlier of the Microwave Research Center in Marlborough, New Hampshire. Low-power microwaves only penetrate (贯穿) the skin (low-power microwave penetration in a ham is about 0.2 inches, for example) and with no negative effects.
To test this idea, Buffler subjected himself to microwaves in a special room using a standard 500-watt, 2459 MHz magnetron (磁控管). He found that a person will start to feel warmth at about 20 kilowatts per square centimeter (mw. / sq. cm. ) ; a satisfactory feeling of warmth occurs between 35 and 50 mw. / sq. cm. By comparison, a person standing in noonday summer sun feels the amount of 85 mw. / sq. cm. And a frozen meat pie in your microwave oven receives about 1000 mw. / sq. cm.
In houses of the future, each room could be provided with its own magnetron, says Buffler. When you stepped into the living room, for example, a motion detector (运动感应器)would turn on the magnetron, filling the room with low-power microwaves. In the same way that a microwave oven heats up a hamburger, but not the plate it’s on, you would feel warmth from the microwaves without changing the temperature of your coffee table. (You could, however, make your favorite easy chair even more comfortable by treating it with a radiation-absorbing chemical.)
While it might be some time before homeowners are comfortable enough with the idea to set up whole-body microwave heaters in houses, Buffler says microwaves may attract livestock(家畜) farmers. Lambs that are born outdoors in winter, for example, are frequently lost to cold. Microwaves could warm the lambs safely and quickly. Which of the following can tell the main idea of the passage?
A.A new heating system. |
B.A new microwave oven. |
C.A popular technique. |
D.The magnetron. |
According to Paragraph 2, which of the following does not describe the characteristics of a microwave heater?
A.It directly heats people in a room. |
B.It heats walls and furniture in a room. |
C.It is safe. |
D.It saves energy. |
The test conducted by Buffler shows that when a person feels comfortable warmth, he receives about ________________.
A.20 mw. / sq. cm. | B.40 mw. / sq. cm. |
C.60 mw. / sq. cm. | D.85 mw. / sq. cm. |
According to Paragraph 4, which of the following fills the room with low-power microwaves?
A.The magnetron. |
B.The motion detector. |
C.The microwave oven. |
D.The radiation-absorbing chemical. |
Which of the following statements about
microwave heaters would Buffler most probably agree with?
A.Microwave heaters will soon be widely used by homeowners. |
B.Microwave heaters sometimes make people feel uncomfortable. |
C.Perhaps microwave heaters will be first used by livestock farmers, who wish to protect their lambs in winter. |
D.Microwave heaters cannot be accepted by the public because they are somewhat unsafe. |
People fell in love with Elizabeth Taylor in 1944, when she starred in National Velvet-the story of Velvet Brown, a young girl who wins first place in a famous horse race, At first, the producers of the movie told Taylor that she was too small to play the part of Velvet. However, they waited for her for a few months as she exercised and trained—and added three inches to her height in four months! Her acting in National Velvet is still considered the best by a child actress.
Elizabeth Taylor was born in London in 1932. Her parents, both Americans, had moved there for business reasons. When World War II started, the Taylors moved to Beverly Hills, California, and there Elizabeth started acting in movies. After her success as a child star, Taylor had no trouble moving into adult(成人)roles and won twice for Best Actress: Butterfield 8(1960) and Who’s Afraid of Virginia Woolf ? (1966)
Taylor’s fame(名声)and popularity gave her a lot of power with the movie industry, so she was able to demand very high pay for her movies. In 1963, she received $1 million for her part in Cleopatra—the highest pay received by any star up to that time.
Elizabeth Taylor is a legend (传奇人物) of our time. Like Velvet Brown in National Velvet, she has been lucky, she has beauty, fame and wealth. But she is also a hard worker. Taylor seldom acts in movies any more. Instead, she puts her time and efforts into her businesses, and into helping others — several years ago, she founded an organization that has raised more than $40 million for research and education. The producers didn’t let Taylor play the part of Velvet at first because they thought she ____.
A.was small in size | B.was too young |
C.did not play well enough | D.did not show much interest |
What Elizabeth Taylor and Velvet Brown had in common was that they were both _____.
A.popular all their lives | B.famous actresses |
C.suecessful when very young | D.rich and kind-hearted |
Taylor became Best Actress at the age of .
A.12 | B.28 | C.31 | D.34 |
In her later life , Elizabeth Taylor devoted herself to .
A.doing business and helping others | B.turning herself into a legend |
C.collecting money for the poor | D.going about research and education work |
Adult butterflies use their senses of sight, touch, hearing, smell, and taste to survive in the world, find food and mates, lay eggs in an appropriate place, migrate, and avoid hungry predators.
Sight
Butterflies have large, compound (multifaceted) eyes, which allow them to see in all directions without turning their heads. Like most insects, butterflies are very nearsighted, so they are more attracted to a large stand of flowers rather than individual plants. Butterflies do not "see" colors such as red, green, and yellow, but sense polarized(偏振的) light, which indicates the direction the sun is shining, as well as ultraviolet light, which is present on many flowers and guides butterflies to nectar (花蜜)sources.
Smell
Butterflies have a very well-developed sense of smell, but it's not in their nose (since they don't have one). Sense receptors located in their antennae, feet, and many other parts of the body help butterflies find food (usually flower nectar), and mates (the female smells the male's pheromones).
Taste
Butterfly's feet have sense organs that can taste the sugar in nectar, letting the butterfly know if something is good to eat or not. Some females also taste host plants in order to find appropriate places to lay their eggs. Adult butterflies and moths feed using a proboscis, a long, coiled tube. Butterflies force blood into the tube to straighten it out, allowing them to feed. Butterflies get all their food from this tube.
Hearing
Butterflies don't have ears. Instead they "hear" sounds through their wings by sensing changes in sound vibrations.
Butterflies may possess senses we don't even know about yet because their anatomy is very different than ours, and therefore difficult to understand when perceived through our own human senses. From the passage we can know that butterflies can see_____
A.thing beh![]() |
B.thing in the distance |
C.most bright colors | D.flower nectar from a distance |
Butterflies can easily find food resources by using their______.
A.sense organs of sight and smell | B.sense organs of sight and taste |
C.sense organs of smell and hearing | D.sense organs of smell and taste |
How do butterflies feed themselves?
A.by using their feet | B.by using a tube. |
C.by using sense receptors | D.by using their wings. |
What is the passage mainly about?
A.The food sources of butterflies. | B.The habits of butterflies. |
C.The unusual body of butterflies. | D.the sense of butterflies. |
In the long discussion of water on the Moon, a new study contradicts(与……相矛盾)) some recent reports that say the Moon had water at the time of its formation. A group of researchers reported in the journal Science that when the Moon was created, some 4.5 billion years ago, there was not much hydrogen(氢气) on it, and therefore no water.
The researchers surveyed and evaluated this by analyzing chlorine isotopes(氯同位素) found in lunar rock samples from Apollo missions. The range of chlorine isotopes in lunar samples was 25 times that found in samples from Earth.
If the Moon had significant levels of hydrogen, as Earth did, this range would have been far less, said Zachary D Sharp, a scientist in the Department of Earth and Planetary Sciences at the University of new Mexico and the study’s lead authour.
The chlorine would have stuck together with hydrogen, forming compounds like hydrogen chloride, and escaped from the Moon’s surface, he said. The abundance of chlorine indicates a lack of hydrogen and water.
“ The amount of water on the Moon was too low for life to possibly have existed there,” he said.
Most scientists believe the Moon was formed when a large object stuck Earth, breaking off a chunk(a vast piece) that has since orbited Earth.
On Earth, goes one theory, water was released as steam form molten basalts(玄武岩) over time, eventually forming bodies of water.
“An understading of whether the Moon was dry or wet will help us understand how water appeared on Earth,” Dr Sharp said. A new study indicates that _____ on the moorn.
A.there is plenty of water | B.water is unlikely to exist |
C.water existed in the past | D.there is a little water now |
The author would like to tell us ______ through the sixth paragraph.
A.why there is no water on the Moon | B.how the Moon was formed |
C.when the Earth struck the Moon | D.where the Moon orbited |
Which is NOT true according to the passage?
A. Zachary D. Sharp, a scientist of New Mexico was in charge of the new study.
B. Chlorine isotopes in lunar samples are 25 time larger than those on the Earth.
C. The more aboundant chloride, the shorter hydrogen and water.
D. The new study is benificial to understand how water appeared on Earth. What can we learn from the passage?
A.There is enough water on the Earth. |
B.Hydrogen chloride easily escaped from the Moon’s surface. |
C.The Earth had significant levels of hydrogen. |
D.Water on the Earth is directly from molten basalts. |