英语六级考试模拟试卷1.doc

　　　　　　 六级考试模拟试卷1

Part I  Writing     (30 minutes)
注意：此部分试题在答题卡1上。
Directions：For this part, you are allowed thirty minutes to write a composition on the topic Psychological Problems among College Students. You should write at least 150 words, and base your composition on the outline given below:

1. 目前很多大学生存在着较严重的心理问题
2. 造成这些心理问题的原因
3. 应该采取什么措施来解决这些问题

Part II Reading (skimming and scanning) (15 minutes)
Directions：In this part, you will have 15 minutes to go over the passage quickly and answer the questions on Answer Sheet 1. For question 17,choose the best answer from the four choices marked A）,B）,C）,and D）.For questions 8—10,complete the sentences with the information given in the passage.

Main Energies for the Body

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 oxidized 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 mobilized 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 synthesized 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 synthesized 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.

Vitamin Categories
  Vitamins cannot be synthesized 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 utilize 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 A
  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.

Vitamins D
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.

Vitamins K
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.

Vitamins C
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.

Vitamins B
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. An adult needs about 12,000kJ of energy a day from ________.
A. the cell B. the respiring process of carbohydrates
C. fats in the cell D. a balanced diet
2. Carbohydrates are ultimately absorbed into cells in the process of _______.
A. digestion B. respiration C. oxidization D. mobilization
3. The Essential Amino Acids which build part of proteins can be obtained from______.
A. stomach B. body tissues C. the body D. the diet
4. The ultimate cause of kwashiorkor is lack of ________.
A. protein B. carbohydrates C. vitamins D. diet
5. Vitamins are called “micronutrients” in that _________.
A. excessive fat soluble vitamins can be excreted in the urine
B. the body only requires small amount of vitamins
C. a dose of 3300mg of vitamins can be considered toxic
D. the high concentrations of water soluble vitamins are toxic
6. Night blindness is a disease normally caused by lack of __________.
A. fat soluble vitamins B. water soluble vitamins C. vitamin A D. innate disability
7. The main function of vitamin D is to prevent adults from ________.
A. the growth of strong bones B. fracture
C. a progressive softening of the bones D. calcium uptake from the gut
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 _______________.

Part III Listening Comprehension (35mins)
Section A
Directions: In part A, you will hear short conversations between two people. After each conversation, you will hear a question about the conversation. The questions and the questions will not be repeated. After you hear a question, read the four possible answers in your test book and choose the best answer. Then, on your answer sheet, find the number of the question and fill in the space that corresponds to the letter of the answer you have chosen.
11. (A) She doesn't want to waste her film.
(B) She already took a picture of the mountains.
(C) She doesn't have any more film.
(D) She doesn't know how to use the camera.
12. (A) he didn't know what hospital Bill was in
(B)he took Bill to the hospital.
(C)He's sorry the woman hurt herself.
(D) He forgot to call the woman.
13. (A) Borrow her book.
(B) Check the classroom again.
(C) Buy a new book.
(D) Ask about the book at the information desk.
14. (A) Spend more time working on calculus problems.
(B) Talk to an advisor about dropping the course.
(C) Work on the assignment with a classmate.
(D) Ask the graduate assistant for help.
15 .(A) He has already finished his report.
(B) He hasn't chosen a topic for his report.
(C) The woman's report is already long enough.
(D) The woman will have time to finish her
16. (A) Stay in the dormitory.
(B) Find out the cost of living in the dormitory.
(C) Ask for a reduction in her rent.
(D) Move into an apartment with a roommate.
17. (A) They're extremely noisy.
(B) They should have arrived by now.
(C)They should be allowed to fly there.
(D)They're not on a definite schedule.
18. (A) He already has plans for Saturday night.
(B) The woman should decide where to eat Saturday.
(C) The woman should ask her brother for a suggestion.
(D) He will make a reservation at the restaurant.
Long conversations
Conversation I
19 (A) She’s writing research papers
(B) She’s working on a conservation project
(C) She’s studying for exams
(D) She’s doing her biology homework
20 (A) She doesn’t know which topic to choose
(B) Her assignments are due on the same day
(C) She’s concerned about the spotted owl
(D) She dislikes her economics class
21 (A)A scarcity of jobs in their field
(B)Inadequate training in methods of biological research
(C)Difficulties in classifying all of the varieties of owls
(D)A lack of funding for their work with endangered species
22 (A)It has numerous traits in common with the spotted owl
(B)Its population is increasing
(C)It may not survive without special efforts of conservationists
(D)Its role in the chain of evolution has not yet been examined
Conversation II
23. (A) They're classmates.
(B) They're roommates.
(C) They're cousins.
(D) They're lab partners.
24. (A) He couldn't decide on a topic for his paper.
(B) He thought his paper was late.
(C) He hadn't heard from his family in a while.
(D) He thought the woman had been ill.
25. (A) To find their way back to the nest.
(B) To locate plant fibers.
(C) To identify kinds of honey.
(D) To identify relatives.

Section B Passage comprehension
Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.
Passage One
Questions 26 to 29 are based on the passage you have just heard.
26. (A) Watch a slide show about trees.
(B) Learn how to prevent Dutch elm disease.
(C) Study the history of the campus buildings and grounds.
(D) Look at examples of trees on campus.
27. (A) History.
(B) Physical education.
(C) Botany.
(D) Architecture.
28. (A) Its leaves are yellow.
(B) Its leaves are lopsided.
(C) It is very tall.
(D) It is not an angiosperm.
29. (A) It has grown too tall for its designated space.
(B) It may be diseased.
(C) Its branches are being broken off.
(D) It no longer hears from.
Passage Two
30. (A) Jefferson's views about commercialized agriculture.
(B) International trade in the nineteenth century
(C) Improvements in farm machinery in the United States.
(D) Farmers' loss of independence
31. (A) Crop production became increasingly specialized.
(B) Economic depressions lowered the prices of farm products.
(C) New banking laws made it easy to buy farmland.
(D) Th