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六级快速阅读冲刺20篇附答案

六级快速阅读题型实战练习（1）

Pizza Hut was started in 1958, by two brothers in Wichita, Kansas. Frank and Dan Carney had the idea to open a pizza parlor. They borrowed $600 from their mother, and opened the very first Pizza Hut. In 1959, the first franchise unit opened in Topeka, Kansas. Almost a decade later, Pizza Hut would be serving one million customers a week in their 310 locations. In 1970, Pizza Hut was put on the New York Stock Exchange under the ticker symbol PIZ.

In 1986, Pizza Hut introduced delivery service, something no other restaurant was doing. By the 1990's Pizza Hut sales had reached $4 billion worldwide. In 1998, Pizza Hut celebrated their 40th anniversary, and launched their famous campaign "The Best Pizzas Under One Roof." In 1996, Pizza Hut sales in the United States were over $5 million. Out of all the existing pizza chains, Pizza Hut had the largest market share, 46.4%. However, Pizza Hut's market share has slowly eroded because of intense competition from their rivals Domino's, Little Caesar's and newcomer Papa John's. Home delivery was a driving force for success, especially for Pizza Hut and Domino's.

However, this forced competitors to look for new methods of increasing their customer bases. Many pizza chains decided to diversify and offer new non-pizza items such as buffalo wings, and Italian cheese bread. The current trend in pizza chains today is the same. They all try to come up with some newer, bigger, better, pizza for a low price. Offering special promotions and new pizza variations are popular today as well. For example, chicken is now a common topping found on pizzas.

In the past, Pizza Hut has always had the first mover advantage. Their marketing strategy in the past has always been to be first. One of their main strategies that they still follow today is the diversification of the products they offer. Pizza Hut is always adding something new to their menu, trying to reach new markets. For example, in 1992 the famous buffet was launched in Pizza Hut restaurants worldwide. They were trying to offer many different food items for customers who didn't necessarily want pizza.

Another strategy they used in the past and are still using is the diversification of their pizzas. Pizza Hut is always trying to come up with some innovative way to make a pizza into something slightly different - different enough that customers will think it’s a whole new product. For example, let's look at some of the pizzas Pizza Hut has marketed in the past. In 1983, Pizza Hut introduced their Pan Pizza, which had a guarantee of being ready to eat in 5 minutes when dining at Pizza Hut restaurants. In 1993, they introduced the "BigFoot," which was two square feet of pizza cut into 21 slices. In 1995, they introduced "Stuffed Crust Pizza," where the crust would be filled with cheese. In 1997, they marketed "The Edge," which had cheese and toppings all the way to the edge of the pizza. Currently, they are marketing "The Big NewYorker," trying to bring the famous New York style pizza to the whole country.

Another opportunity that Pizza Hut has is their new ordering online system. Anyone with Internet access can order whatever they wish and get it delivered to their house without even speaking to someone. This program has just been started, so we do not have any numbers to support whether or not it will be a success.

Lastly, Pizza Hut has always valued customer service and satisfaction. In 1995, Pizza Hut began two customer satisfaction programs: a 1-800 number customer hotline, and a customer call-back program. These were implemented to make sure their customers were happy, and always wanted to return. In our plan, we will first give a situation analysis of current and relevant environmental conditions that affect our plan. Next, we will give a brief analysis of the current fast food industry, and any trends or changes that might occur in

the future.

However, the fact that Pizza Hut does have a restaurant to run is also a weakness. Pizza Hut has higher overhead costs, due to the restaurant that other competitors don't have to deal with. Another result of higher overhead costs is higher prices Pizza Hut must charge. Obviously, Pizza Hut is not the low cost producer. They rely on their quality pizza and good service to account for their higher prices.

An indirect weakness that Pizza Hut has is that they have lost a lot of their customers and market share due to such intense competition with competitors. Pizza Hut's opportunities are almost endless. They can increase revenue with their new innovative pizzas, and increase brand loyalty with good customer service.

Pizza Hut's number one threats are from their competitors. Currently, their closest competitor is Domino's Pizza. Domino's main competitive advantage over Pizza Hut is their price. It is generally lower than Pizza Hut. Also, Domino's was very profitable when they ran the promotional deal of delivering a pizza within 30 minutes. However, many lawsuits have been filed against Domino's in the past for reckless driving by their drivers, so Domino's withdrew the promotion. Little Caesar's is another one of Pizza Hut's competitors, right behind Domino's in market share. Little Caesar's is famous for offering large quantities of pizza for less money. Other competitors include Papa John's, Sbarro, and Pizza Inn.

A problem facing all of the pizza chains is that each of their individual competitive advantages are pretty much everyone's competitive advantages. Most if not all the top pizza chains offer free delivery, and always have some sort of promotional deal offering large pizzas at reduced prices. Other competitors to take into consideration are frozen pizzas and make-it-yourself pizzas that are purchased in grocery stores. Some examples of these are Tombstone Pizzas, Boboli, and Di'Gornio pizzas.

1. Pizza Hut expanded its business into many parts of the country by the time of 1969.

2. Pizza Hut has always dominated the market and is free of challenge.

3. Fruits and salads are now commonly served at pizza restaurants.

4. The diversification strategy is to be the first mover.

5. In Pizza Hut, a Pan Pizza was ___________ to serve in 5 minutes.

6. If you want a pizza from Pizza Hut delivered directly to your house, you have to have ________ in the first place.

7. In order to make sure their customers were happy, Pizza Hut introduced ________________.

8. The higher overhead costs of Pizza Hut obviously accounted for ______________.

9. The reason why Domino’s withdrew their promotion was that they suffered legally from _____________.

10. Major pizza makers have to face the problem that their competitive advantages are _________.

六级快速阅读题型实战练习（2）

Passage Two

The world was stunned by the news in the summer of 1995, when a British embryologist named Ian Wilmut, and his research team, successfully cloned Dolly the sheep using the technique of nuclear transfer. Replacing t he DNA of one sheep’s egg with the DNA of another sheep’s the team created Dolly. Plants and lower forms of animal life have been successfully cloned for many years, but before Wilmut's announcement, it had been thought by many to be unlikely that such a procedure could be performed on larger mammals and life forms. The world media was immediately filled with heated discussions about the ethical implications of cloning.

Some of the most powerful people in the world have felt compelled to act against this threat. President Clinton swiftly imposed a ban on federal funding for human-cloning research. Bills were put in the works in both houses of Congress to outlaw human cloning because it was deemed as a fundamentally evil thing that must be stopped. But what, exactly, is bad about it? From an ethical point of view, it is difficult to see exactly what is wrong with cloning human beings. The people who are afraid of cloning tend to assume that someone would, for example, break into Napoleon's Tomb, steal some DNA and make a bunch of emperors. In reality, infertile people who use donated sperm, eggs, or embryos would probably use cloning. Do the potential harms outweigh the benefits of cloning? From what we know now, they don't. Therefore, we should not rush placing a ban on a potentially useful method of helping infertile, genetically at-risk, homosexual, or single people to become parents.

Do human beings have a right to reproduce? No one has the moral right to tell another person that they should not be able to have children, and I don't see why Bill Clinton has that right either. If humans have a right to reproduce, what right does society have to limit the means? Essentially all reproduction done these days is with medical help at delivery, and even before. Truly natural human reproduction would make pregnancy-related death the number one killer of adult women.

Some forms of medical help are more invasive than others. With in-vitro fertilization, the sperm and egg are combined in a lab and surgically implanted in the womb. Less than two decades ago, a similar concern was raised over the ethical issues involving "test-tube babies". Today, nearly 30,000 such babies have been born in the United States alone. This miracle has made many parents happy. So what principle says that one combination of genetic material in a flask is acceptable, but not another?

Nature clones people all the time. Approximately one in 1000 births is an identical twin. However, despite how many or how few individual characteristics twins have in common, they are still different people. They have their own identities, their own thoughts, and their own rights. They enter different occupations, get different diseases, and have different experiences with marriage, alcohol, community leadership, etc. Twins have different personalities as would cloned individuals. Even if someone cloned several Napoleons, each would be different and even more unique than twins; the cloned child would be raised in a different setting. Therefore, cloning does not rob individuals of their personality.

Perhaps the strongest ethical argument against cloning is that it could lead to a new, unfamiliar type of family relationship. We have no idea what it would be like to grow up as the child of parents who seem to know you from the inside. Some psychological characteristics may be biologically, or genetically, based. The parent would know in advance what crises a cloned teenager could go through and how he or she will respond. Because the parents may understand what the child is going through, to greater degree than most parents, it may produce a good and loving relationship in the long run. On the other hand, most children want to have their own space. Simply because a family relationship is new and untried is no reason to automatically condemn it. In the past, many types of family relationships were considered harmful, but later showed to cause no harm to the children. Among these is joint custody after divorce, gay and lesbian parenting, and interracial adoption. As with adoption, in-vitro fertilization, and the use of donor sperm, how the child will react to the news about his or her arrival in this world will depend on how the parents feel about their mode of reproduction. Parents and children may adjust to cloning far more easily than we might think, just as it happened with in-vitro fertilization.

One recurring image in anti-cloning propaganda is of some evil dictator raising an army of cloned warriors. But who is going to raise such an army. Clones start out life as babies. It is much easier to recruit young adults than to take care of babies for twenty years. Remember that cloning isn't the same as genetic engineering. No one can make another superman and his super powers might have a slim chance of being genetically determined, but nothing is certain.

Some might think that cloning is playing God. However, can you really say that you know God's intentions? There is substantial disagreement as to what God’s will is. Ar mstrong wrote, anyone who has truly proved that God exists, that God isn't only Creator, but Life-giver, Designer, Sustainer, and Ruler over all his creation, knows that the human family began with one man, and that together with him a wife, miraculously created from his own body and as unique and original a creation as Adam himself, formed the first family. Though God's miraculous creation of Eve was far from cloning, it is interesting to note in passing that God's own Word says He used Adam's rib-physical bone and tissue - to create Eve?

Another argument against cloning is that it would only be available to the wealthy and, therefore, would increase social inequality. What else is new? This is the story of American health care. We need a better health care system, not a ban on new technologies. Hopefully our new president will help us with this problem as well.

The U.S. Federal Government should not deem human cloning and cloning research illegal. It may provide a way for completely sterile or homosexual individuals to reproduce, and will probably provide valuable basic research and possible spin-off technologies related to reproduction and development. Our society has respected general rights to control one’s body regarding reproduction, a nd finally prohibiting it would violate the fundamental freedom of scientific inquiring.

Will human cloning be done? Undoubtedly. The technique used in sheep cloning does not require a highly sophisticated laboratory. Since the United States government does not support research on human cloning, and the United Kingdom, France, and Germany have banned it, the research making cloning possible may take place in Asia, Eastern Europe, or the East. Much cloning may also take place in secret, and will occur regardless of United States policies. Approximately eighty percent of Americans feel that cloning is wrong. However, the vast majority of people, including those who rail against cloning research, owe their lives to previous medical discoveries. Don't let the forces of ignorance and fear turn us away from new types of research.

1. Cloning large mammals and life forms had been practiced for many years by the time Dolly was cloned.

2. The tomb of Napoleon has already been broken into and samples of genes have been collected.

3. The introduction of human cloning may reduce a great amount of death of adult women.

4. In-vitro fertilization is much better than natural birth in terms of safety.

5. Identical twins can still have different personalities because they are brought up ________________.

6. The reason why in a family with a cloned child there is likely to be a good and loving relationship is the parents’ better understanding of _______________________.

7. Compared with cloning human and bringing them up as an army, it would be much cheaper to ______________________________.

8. Some worry that human cloning as a potential privilege for the rich might contribute to _____________.

9. The illegalization of human cloning by the government may erase the hope of people like _________________________.

10. Since human cloning can not be done in the U.S., the U.K., France and Germany, researchers can still conduct their researches in Asia, Eastern Europe, or the East, or in ___________.

Passage Three

Handguns and other firearms have a long tradition in American civilization. The right to bear arms is

an American right featured in the second Amendment of the Constitution. In the 18th century, when the constitution was written, times were different; there was a need for armed citizens to insure the safety of the society as a whole. Contemporarily the police department preserves the safety of society and the need for armed citizens is out of date. The founding fathers of the Constitution could presumably never imagine the horrendous outcome of their actions. Every year too many lives are claimed as the result of the American government’s inability to fully face up to effects of the i ssue. Compared to other western countries that have considerably stricter gun control laws America is still viewed as "The Wild-Wild West".

The growing gun related death toll in the U.S. has to come to a turning point. Stripping away the constitutional right to bear arms might have the effect that only criminals will have access to guns. It is important to understand that in a society where both criminals and law abiding citizens have access to guns the likeliness of an innocent person getting shot, when both parties are waving guns, is probably greater than if only criminals have guns. A ban on firearms might not be appealing as a short-term solution but it is important that people don’t limit their thinking to their generation and not think about t he safety of their children, grandchildren and the society people are creating today for them to live in.

The main obstacle in removing firearms from citizens in the U.S. is the second Amendment of the Constitution. It reads: "A well regulated Militia being necessary to the security of a free State, the right of the people to keep and bear Arms shall not be infringed." The second Amendment can be interpreted as every citizen right to bear arms. However the key word is "Militia", meaning soldiers or defenders of the State. In the late 18th century, when the Constitution was written, times were very different than those of contemporary America. People were scared of possible invasions from Native Americans, the English, and other nationalities. By "a well regulated Militia" the founding fathers probably meant that citizens could have a muscot standing in the corner just in case anything would happen. Note that the writers of the Constitution added, "a well regulated" in front of the word Militia. That would most likely reveal a controversy in writing this Amendment, some of the founding fathers might have foreseen the possibility of a misinterpretation of this Amendment.

In the U.S. there are approximately 200 million privately owned guns, which is statistically close to a gun per person and places more than one gun per home on average. In other words, guns are all around. This affects, without a doubt, the whole society structure and the citizens that live within its boundaries.

The children that live within a gun infested society are going to suffer the consequences. In fact, kids between the ages 16 and 19 have the highest handgun victimization rate among all age groups. It’s not hard to understand why, since there are on average more than one gun per household, kids are likely to find firearm and in some cases even use it.

In March 1998 two children, 11 and 13 years of age gunned down a total of 13 people in a school in Jonesboro, Arkansas. Of the 13, nine survived and five people, classmates and teacher, died as a result of the shooting. One of the boys had taken two rifles from his grandfather. They positioned themselves about 100 yards from the schoolyard and when the bell for recession sounded and people started to exit the school building the two boys opened fire. This is a horrendous event that proves that if guns are present within a household or within a family, odds are that kids will perhaps be curious enough to actually capitalize on them.

In October, 1997 a 16 year old boy shot and killed his girlfriend and her best friend while they were exiting a Mississippi school leaving six others wounded. The spontaneity of young children and guns are a lethal combination as illustrated in these two examples.

In a study made across high schools in Seattle, 47% of males and 22% of females reported that they had easy access to handguns and 11.4% were gun-owning males. The access to guns might prove to be deadly for both innocent bystanders and the holder of the gun. Children should not be able to own guns. One of the prerequisites for owning a gun should be that the person is responsible enough to own a firearm. Since there are no guarantees for that, guns should only be issued in extensively controlled forms otherwise the

government jeopardizes the safety of the people they've sworn to protect.

In the ages 10-14 72%, and in the ages 15-19, 85% of all homicides are committed with firearms. In addition to that 60 % of all suicides among youths is committed with a handgun. The total firearm death rate concerning white males in their teens now exceed natural causes. These are alarming statistics show the brutal reality of firearms in the U.S.

A study made by the American Psychological Association, Commission on Violence and Youth showed, in a study made in Seattle in 1993, that 6% of males in the 11th grade had at least once brought a handgun to school. More than 1 in 20 had brought a handgun to school, in other words the prevalence of guns across the schools is nothing less than a common sight. How does that affect the rest of us? Parents might just get the news from police officers that their son or daughter had become victim to a stray bullet while attending history class.

The lawmakers in the United States are addressing the problem by putting up metal detectors in schools. In the case of metal detectors, officials have realized that preventing the possession of firearms inside the boundary of the school is necessary for the safety of the students and teachers. This is a temporary solution to ever-growing problem. The risk of a student or a teacher getting shot inside the school property has probably been reduced, which is positive. But the fact remains that outside of the school property the risk of being victimized is growing every year.

In order for these types of events not to occur legislators and other professionals are emphasizing precautionary actions of the gun owners and most of the time a ban on guns isn’t mentioned. "Why I should be denied the same right my father and grandfather had?" Because times have changed, guns are not solely created and used for hunting anymore, and with today’s technology, in the form of automatic guns and high impact ammunition, guns have become deadlier, which leaves a greater responsibility on the owners. Are people ready for that responsibility?

1. Nowadays it is the armed citizens who are responsible for the overall social safety.

2. The legislation should forbid individual citizens to have guns because it is relatively less detrimental.

3. According to the second Amendment of the Constitution, American citizens have the right to bear arms and to use them whenever they want.

4. It can be told from the statistics that for each American family there is approximately one gun.

5. The Jonesboro shooting case demonstrates that if guns are kept in a household, kids would probably ________________________________.

6. It is improper for a child to own a gun because they are not _____________________.

7. _______ white teenage boys die from firearm attack _________ from natural causes.

8. The fact that more than a twentieth of the 11th grade students have brought a gun to school means that guns are actually ____________________.

9. Although lawmakers addressed the problem by using metal detectors within the school, It is still highly possible to ____________ out of school.

10. The reason why today’s individuals should not be allowed to keep guns is that guns are no longer used for _________ alone.

六级快速阅读题型实战练习（4）

Passage Four

Our galaxy is a gigantic agglomeration of stars and planets whose numbers will probably never been known. Currently we estimate this number to be about thirty billion. Scientists have estimated that the diameter of our galaxy, if it were to be traveled, would take us about fifty thousand light years and the thickness to be about fifteen to twenty light years.

We live in small part of the Milky Way Galaxy, which is referred to as a solar system. Our solar system is made up of nine planets and 31 moons, which orbit the center of galaxy. At the center of our

galaxy is our Sun, which is approximately twenty-five thousand light years from our solar system.

These nine major planets in order from the center are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

Mercury is the planet nearest to the Sun. As it orbits the Sun, it does not rotate, keeping the same face of the planet toward the Sun at all times. This means that one side of the planet has a continual burning day of 900 °F, and the other side a continual night and a deadly cold of 450° F below zero. Mercury is the fastest traveling of the nine planets making one full orbit around the Sun in only eight days. Life on mercury would be impossible. If you could live where the night meets the day and survive the extreme conditions, you would need dark goggles to protect you eyes from the extreme light. Mercury has little or no atmosphere to diffuse the sunlight. You would also weigh considerable less due to the lack of gravity. A person weighting 100 pounds on Earth would weigh 27 pounds on Mercury.

Looking into the night sky you will notice Venus, the brightest star in the sky, and the second planet from the Sun. Venus can only be seen at certain times of the day either at dawn or at Sunset. In physical characteristics, Venus is most like earth with a diameter of seven thousand six hundred miles, and gravity the same as earth. It is located a distance of sixty-seven million miles from the Sun and makes one complete orbit around the Sun in two hundred twenty five days. A single day on Venus can last up to two hundred and twenty five earth days due to its slow rotation. The atmosphere appears to consist of mostly nitrogen and carbon dioxide. This is due to the lack of life on the planet.

The best time to view Venus comes every one hundred and twenty years as it passes between the Earth and the Sun. The last time to best view it was on June 7, 2004.

Earth, the third planet form the Sun is our home planet. Earth is the only planet in our solar system known to sustain life. Under the layer of atmosphere that surrounds the planet we are able to provide all the necessary components to make life sustainable. Earth is the fifth larges planet in the solar system. Its diameter is just a few hundred kilometers larger than Venus. Earth rotates on its axis one complete revolution in a twenty-four hour period and orbits the Sun in three hundred and sixty five days.

Mars is the fourth planet from the Sun and is the closest neighbor to earth. Every seventeen years Mars reaches its closest point to earth in its orbit around the Sun at thirty-five million miles.

Mars is a small planet that has a red glow. It makes one complete orbit around the Sun in six hundred and eighty seven days. Oxygen and water vapor have been detected in the atmosphere of Mars, and a yellowish fog and clouds move around the planet indicating that the planet has different types of weather and seasons like the earth. A single day on Mars is very much like a day on earth lasting twenty-four hours and thirty-seven minutes, however, a year on Mars is twice as long as one year on earth.

Jupiter the fifth planet from the Sun gets its name from the Father of the Greek Gods. Jupiter, which orbits four hundred eighty-three million miles from the Sun, is the biggest of all the planets in our solar system. It has a diameter of eighty-nine thousand miles and a volume of thirteen times that of earth. Jupiter orbits the Sun every twelve years. Its atmosphere is thousands of miles thick and is made up of mainly hydrogen. The surface temperature is about -205°F. There are no seasons on Jupiter, but it has floating clouds of ammonia and methane gas.

Saturn, even though it is the sixth planet form the Sun, it shines so brightly because of its size. Its diameter is seventy-one thousand five hundred miles. The planet itself is golden in color and is the brightest yellow star in the night sky.

Saturn makes one complete revolution on its axis every ten hours and takes twenty-nine and one half

days to complete one orbit around the Sun. The gravitational pull of this planet is most like that of Jupiter. It has a volume that is eight hundred times that of earth, but has a volume that is one hundred times lighter than earth.

Saturn has two rings that surround the planet, but never touch it. They are located outside the atmosphere and above the equator. These rings are only about ten miles thick, which makes them transparent, only being seen with the use of a telescope. The ring closest to the planet is about seven thousand miles and very thin. A black band separates the inner ring from the outer ring, which is wider and brighter. It is believed that the rings are made up of crystals of ice or dust particles.

Uranus is the seventh planet form the Sun. The name Uranus comes from Greek mythology. Uranus was the ¨God of the Heavens.〃

Uranus is situated one thousand seven hundred and eighty two miles form the Sun and completes one orbit around the Sun every eighty-four years. The size of this planet is four times that of earth, but has the same force of gravity on the surface as earth. There are five moons that orbit this planet. The largest one is Titania.

Neptune, the eighth planet from the Sun, is invisible to the naked eye. It is located some two thousand seven hundred and ninety-three million miles form the Sun. A single orbit around the Sun takes one hundred and sixty-five yeas to complete. This planet only receives one nine-hundredth of the heat and Sunlight as the earth.

Pluto was the ninth planet from the Sun. The name Pluto comes from the Roman God who was the ruler of the under world. On Thursday, August 24, 2006, however, the International Astronomical Union (IAU) met in Prague voted finalizing the guidelines of planetary classification, thus reorganizing Pluto into a new category of “dwarf planet”.

Pluto is located three thousand six hundred and seventy million miles form the Sun. It orbits the Sun in total darkness, and is about the same size as Mars and has a diameter two thirds that of Earth’s moon. Due to the distance and size of Pluto, it can only be seen with the use of a twenty-inch telescope.

Pluto disqualified due to its eccentric orbit that crosses with Neptune. In addition to the fact that it is disproportionately smaller than any of its former counterparts in the solar system, it does not qualify as a planet. Otherwise, we might as well qualify Pluto’s moon, Charon as a planet, thus making Pluto and Charon

a binary planet system.

1. If we are to travel from one end of the galaxy circle to the other at the speed of light, it would take us fifty thousand light years.

2. There can not possibly be any form of water in Mercury.

3. Venus is sharing with the earth similar diameter, similar gravity and similar rotation.

4. The speed with which Mars travels round the Sun is twice as fast as that of the earth.

5. Jupiter has an atmosphere, which, unlike that of earth, contains for the most part _____________.

6. Despite the quick rotation of Jupiter, its clouds are still clinging to the planet with the help of __________________.

7. between the inner ring and the outer ring of Saturn there is a ___________________.

8. Compared with that of the earth, the gravity force on the surface of Uranus is _____________.

9. According to the International Astronomical Union, Pluto is no longer seen as a planet; instead, it should be termed as ________________.

10. Its eccentric orbit and its _____________ disqualified Pluto as a planet.

Passage five

A balanced diet is one that provides an adequate intake of energy and nutrients for maintenance of the body and therefore good health. A diet can easily be adequate for normal bodily functioning, yet may not be

a balanced diet.

Carbohydrates

Carbohydrates are a rapid source of energy, they are the body's fuel. The bulk of a balanced diet should be made from carbohydrates. If eaten in an excess of the dietary requirements carbohydrates are easily stored as fats in the cells, although carbohydrate is the first source of energy in the body.

An average adult requires about 12,000kJ of energy a day, most of this is supplied by the respiration of carbohydrates in the cells.

Carbohydrates are used principally as a respiratory substrates, i.e. to be oxidised to release energy for active transport, macromolecule synthesis, cell division and muscle contraction. Carbohydrates are digested in the duodenum and ileum and absorbed as glucose into cells. Sources of carbohydrates such as starch are rice, potatoes, wheat and other cereals. Sugars are also carbohydrates, sources of sugars are refined sugar - sucrose, which is a food sweetener and preservative and fruit sugars - fructose. If the diet lacks carbohydrate stores of fat are mobilised and used as an energy source.

Proteins

Protein is not a direct source of energy in the body, it is used primarily for growth and repair of body tissues while remaining an energy source as a last resort. Proteins fulfill a wide variety of roles in the body. They are broken down in the stomach and intestines to amino acids which are then absorbed. The body can only form 8 amino acids to build proteins from, the diet must provide Essential Amino Acids (EAAs) which are synthesised into proteins which can be structural, i.e. collagen in bone, keratin in hair, myosin and actin in muscle; metabolic enzymes, hemoglobin, protective antibodies and communicative hormones.

Sources of protein include meat, fish, eggs and pulses. The diet needs to provide 8 EAAs as the body is unable to synthesis proteins without these molecules. 2 other amino acids are synthesised from EAAs so if the diet lacks the original EAAs these other two will not be present either. Phenylalanine is converted to tyrosine and methionine is converted to cysteine. Cells draw upon a pool of amino acids for protein synthesis which either come from dietary protein digested and absorbed in the gut and the breakdown of body protein such as muscle. However, unlike fats and carbohydrates there is no store of amino acids for cells to draw on, any amino acid in excess of immediate bodily requirements is broken down into urea and excreted. It is therefore important to maintain the dietary intake of protein everyday. If the body lacks protein, muscle wasting occurs as muscle is broken down.

If protein is lacked in a diet a person develops kwashiorkor which is caused when high levels of carbohydrates are eaten to overcome the lack of protein in the diet. One symptom of kwashiorkor is the abnormal collection of fluid around the abdomen due to the lack of protein in the blood. The body cannot retain water by osmosis and fluid accumulates in tissues causing them to become waterlogged.

Vitamins

Vitamins cannot be synthesised by the body so must be supplied by diet. Vitamins have no common structure or function but are essential in small amounts for the body to be able to utilise other dietary components efficiently.

Vitamins fall into two categories, fat soluble vitamins such as vitamin A, D, E and K which are ingested with fatty foods and water soluble vitamins such as the B group vitamins and vitamin C. Vitamins are known as micronutrients because only small quantities are required for a healthy diet, in fact fat soluble vitamins can be toxic in high concentrations, for example the body stores vitamin A, or retinol, in the liver as it is toxic if kept in high concentrations in the blood stream, a dose of more than 3300mg of vitamin A can be considered toxic. Water soluble vitamins such as vitamin C and B groups vitamins can be excreted in the urine if in excess in the diet.

Vitamins carry out a wide range of functions and prevent specific deficiency diseases. A diet that lacks a certain vitamin is not a balanced diet, vitamins have vital roles in the maintenance of a healthy body.

An example of a deficiency is when the diet does not contain enough, or any vitamin A. Vitamin A is

found in some animal foods such as milk, eggs, liver and fish liver oils, related compounds such as carotenoids e.g. b carotene, are in a wide variety of vegetables such as cabbages, carrots and spinach.

Vitamin A is essential to the proper functioning of the retina in the eye and the epithelial tissues. A lack of vitamin A results in dry, rough skin, inflammation of the eyes, a drying or scarring of the cornea - xerophthalmia, which occurs when the secretion of lubricating tears is stopped, the eyelids become swollen and sticky with pus. Mucous surfaces of the eye may become eroded allowing infection to set in, leading to ulceration and destruction of the cornea. Night blindness - an inability to see in dim light can also occur. Rod cells in the retina of the eye detect light of low intensity, they convert vitamin A into a pigment, rhodopsin, which is bleached when light enters the eye. Rod cells resynthesis rhodopsin, but if there is a deficiency of the vitamin, rod cells can no longer function and the result is night blindness. Epithelial cells use retinol to make retinoic acid, an intracellular messenger used in cell differentiation and growth. Without retinoic acid epithelial cells are not maintained properly and the body becomes susceptible to infections, particularly measles and infections of the respiratory system and gut.

Xenophthalmia is common among children who's diets consist of mainly cereals with little meat or fresh vegetables, this is common in Indonesia, Bangladesh, India and the Philippines.

Vitamin D, or calciferol, is another fat soluble steroid vitamin which functions to stimulate calcium uptake from the gut and its deposition in bone. vitamin D acts as a hormone when converted by enzymes in the gut and liver into an active form of "active vitamin D", which stimulates epithelial cells in the intestine to absorb calcium. vitamin D is therefore essential in growing children's diets to enable the growth of strong bones. Without adequate amounts of vitamin D children can develop rickets, which is the deformation of the legs caused when they lack calcium to strengthen the bones. In adults a lack of vitamin D in the diet can lead to osteomalacia, a progressive softening of the bones which can make them highly susceptible to fracture.

Vitamin D is made by the body when exposed to sunlight and is stored in the muscles, however, if the skin is rarely exposed to the sunlight or is dark little vitamin D is produced. Foods such as eggs and oily fish are all rich in vitamin D.

Vitamin K, phylloquinone, is found in dark green leafy vegetables such as spinach and kale. It is a fat soluble vitamin which is involved in the clotting process of blood. In the intestines bacteria synthesize a number of important clotting factors which need vitamin K. Without vitamin K cuts can fail to heal and internal bleeding can occur.

Vitamin C is a water soluble vitamin, known chemically as ascorbic acid. It is found in citrus fruits such as oranges and lemons, and also in potatoes and tomatoes. The main function of vitamin C is the formation of connective tissues such as collagen. It is also known to be an antioxidant which helps to remove toxins and aids the immune system. A lack of vitamin C leads to Scurvy, a condition experienced by sailors on long journeys when they did not have fruit in their diets. Scurvy causes painful, bleeding gums. As vitamin C is water soluble, it is not toxic in high doses as it can be excreted in the urine, very high doses can however cause diarrhea.

B group vitamins have a wide range of roles acting as co-enzymes in metabolic pathways. They are found in most plant and animal tissues involved in metabolism, therefore foods such as liver, yeast and dairy products are all rich in B group vitamins. Deficiency of B group vitamins include dermatitis, fatigue and malformation of red blood cells.

1. When we have too much of carbohydrates, they are most likely be stored as sugar units.

2. In the process of digestion, carbohydrates are finally turned into cells.

3. The Essential Amino Acids which build part of proteins can be formed by human body.

4. The ultimate cause of kwashiorkor is lack of protein, rather than lack of carbohydrates.

5. There are generally two different kinds of vitamins, they are __________________________.

6. Night blindness is a disease normally caused by lack of _____________.

7. One of the main function of vitamin D is to prevent adults from ________________.

8. Although the human body produces vitamin D normally, it fails to do so if there is not enough ______________.

9. The reason why vitamin C is seen as an antioxidant is that it drives ___________ out of the body.

10. If you are in lack of B group vitamins, you should turn to ________________________.

Passage six

We live in small part of the Milky Way Galaxy, which is referred to as a solar system. Our solar system is made up of nine planets and 31 moons, which orbit the center of galaxy. At the center of our galaxy is our Sun, which is approximately twenty-five thousand light years from our solar system.

These nine major planets in order from the center are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

Mercury is the planet nearest to the Sun. As it orbits the Sun, it does not rotate, keeping the same face of the planet toward the Sun at all times. This means that one side of the planet has a continual burning day of 900 °F, and the other side a continual night and a deadly cold of 450°F below zero. Mercury is the fastest traveling of the nine planets making one full orbit around the Sun in only eight days. Life on mercury would be impossible. If you could live where the night meets the day and survive the extreme conditions, you would need dark goggles to protect you eyes from the extreme light. Mercury has little or no atmosphere to diffuse the sunlight. You would also weigh considerable less due to the lack of gravity. A person weighting 100 pounds on Earth would weigh 27 pounds on Mercury.

The best time to view Venus comes every one hundred and twenty years as it passes between the Earth and the Sun. The last time to best view it was on June 7, 2004.

Mars is the fourth planet from the Sun and is the closest neighbor to earth. Every seventeen years Mars reaches its closest point to earth in its orbit around the Sun at thirty-five million miles.

system. It has a diameter of eighty-nine thousand miles and a volume of thirteen times that of earth. Jupiter orbits the Sun every twelve years. Its atmosphere is thousands of miles thick and is made up of mainly hydrogen. The surface temperature is about -205°F. There are no seasons on Jupiter, but it has floating clouds of ammonia and methane gas.

Jupiter has a bright red distinctive spot that is more than twice as wide as Earth. This mark has astronomers puzzled because there is no reason for the bright spot due to the fact that it does not receive much Sunlight. This spot enables us to see that Jupiter has a very fast rotation. One rotation is completed every ten hours. The forces placed on the planet due to this quick rotation cause the clouds at the equator to bulge like a tire, but due to the gravitational forces of the planet keep the clouds from being cast into space. Saturn, even though it is the sixth planet form the Sun, it shines so brightly because of its size. Its diameter is seventy-one thousand five hundred miles. The planet itself is golden in color and is the brightest yellow star in the night sky.

Saturn makes one complete revolution on its axis every ten hours and takes twenty-nine and one half days to complete one orbit around the Sun. The gravitational pull of this planet is most like that of Jupiter. It has a volume that is eight hundred times that of earth, but has a volume that is one hundred times lighter than earth.

Uranus is the seventh planet form the Sun. The name Uranus comes from Greek mythology. Uranus was the ¨God of the Heavens.〃

Pluto is located three thousand six hundred and seventy million miles form the Sun. It orbits the Sun in total darkness, and is about the same size as Mars and has a dia meter two thirds that of Earth’s moon. Due to the distance and size of Pluto, it can only be seen with the use of a twenty-inch telescope.