READING PASSAGE 2

You should spend about 20 minutes on Questions 14-26, which are based on Reading Passage 2 below.

Water Treatment 2 : Reed Bed

In recent years, it has been shown that plants, more accurately roots, play a crucial part in purifying dirty water before it enters seas and rivers. In 15th-century Britain, dirty water was purified by passing through the wetlands. People began to realize that the “natural” way of water purification was effective. Nowadays subsurface flow wetlands (SSFW) are a common alternative in Europe for the treatment of wastewater in rural areas, Mainly in the last 10 to 12 years there has been a significant growth in the number and size of the systems in use. The conventional mechanism of water purification used in big cities where there are large volumes of water to be purified is inappropriate in rural areas.

The common reed has the ability to transfer oxygen from its leaves, down through its stem and rhizomes, and out via its root system. As a result of this action, a very high population of microorganisms occurs in the root system, in zones of aerobic, anoxic, and anaerobic conditions. As the waste water moves very slowly through the mass of reed roots, this liquid can be successfully treated. The reason why they are so effective is often because within the bed’s root sector, natural biological, physical and chemical processes interact with one another to degrade or remove a good range of pollutants.

Dirty water from households, farms and factories consume a lot of oxygen in the water, which will lead to the death of aquatic creatures. Several aquatic plants are important in purifying water. They not only absorb carbon dioxide and release oxygen into the water, improving the environment for fish, but absorb nutrients from the welter as well. Britain and the G.S. differ in their preference of plants to purify water. Bulrushes (Scirpus spp.) and rushes (Juncus spp.) are excellent water purifiers. They remove excess nutrients from the water as well as oil and bacteria such as Escherichia coli and Salmonella. However, algae grow freely in summer and die off in winter. Their remains foul the bottom of the pool.

Artificial reed beds purify water in both horizontal and downflow ways. The reeds succeed best when a dense layer of root hairs has formed. It takes three years for the roots to fully develop. Which type of wetland a certain country applies varies widely depending on the country in Europe and its main lines of development. Besides the development of horizontal or vertical flow wetlands for wastewater treatment, the use of wetlands for sludge treatment has been very successful in Europe. Some special design lines offer the retention of microbiological organisms in constructed wetlands, the treatment of agricultural wastewater, treatment of some kinds of industrial waste- water, and the control of diffuse pollution.

If the water is slightly polluted, a horizontal system is used. Horizontal-flow wetlands may be of two types: free-water surface-flow (FWF) or sub-surface water-flow (SSF). In the former the effluent flows freely above the sand/gravel bed in which the reeds etc. are planted; in the latter effluent passes through the sand/gravel bed. In FWF-type wetlands, effluent is treated by plant stems, leaves and rhizomes. Such FWF wetlands are densely planted and typically have water-depths of less than 0.4m. However, dense planting can limit the diffusion of oxygen into the water. These systems work particularly well for low strength effluents or effluents that have undergone some forms of pretreatment and play an invaluable role in tertiary treatment and the polishing of effluents. The horizontal reed flow system uses a long reed bed, where the liquid slowly flows horizontally through. The length of the reed bed is about 100 meters. The downside of horizontal reed beds is that they use up lots of land space and they do take quite a long time to produce clean water.

A vertical flow (downflow) reed bed is a sealed, gravel filled trench with reeds growing in it. The reeds in a downflow system are planted in a bed 60cm deep. In vertical flow reed beds, the wastewater is applied to the top of the reed bed, flows down through a rhizome zone with sludge as a substrate, then through a root zone with sand as a substrate, followed by a layer of gravel for drainage, and is collected in an under drainage system of large stones. The effluent flows onto the surface of the bed and percolates slowly through the different layers into an outlet pipe, which leads to a horizontal flow bed where it is cleaned by millions of bacteria, algae, fungi, and microorganisms that digest the waste, including sewage. There is no standing water so there should be no unpleasant smells.

Vertical flow reed bed systems are much more effective than horizontal flow reed- beds not only in reducing biochemical oxygen demanded (BOD) and suspended solids (SS) levels but also in reducing ammonia levels and eliminating smells. Usually considerably smaller than horizontal flow beds, they are capable of handling much stronger effluents which contain heavily polluted matters and have a longer lifetime value. A vertical reed bed system works more efficiently than a horizontal reed bed system, but it requires more management, and its reed beds are often operated for a few days then rested, so several beds and a distribution system are needed.

The natural way of water purification has many advantages over the conventional mechanism. The natural way requires less expenditure for installation, operation and maintenance. Besides, it looks attractive and can improve the surrounding landscape. Reed beds are natural habitats found in floodplains, waterlogged depressions and estuaries. The natural bed systems are a biologically proved, an environmentally friendly and visually unobtrusive way of treating wastewater, and have the extra virtue of frequently being better than mechanical wastewater treatment systems. Over the medium to long term reed bed systems are, in most cases, more cost effective to install than any other wastewater treatment. They are naturally environmentally sound protecting groundwater, dams, creeks, rivers and estuaries.

Questions 14 - 16

4.  

Do the following statements agree with the information given in Reading Passage 2? In boxes 14-16 on your answer sheet, write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this

Questions 17-19

Complete the diagram below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
Downflow Reed Bed System

17. 

18. 

19. 

Question 20 - 24

The advantage of the downflow system is 20 ; however, 21  and 22  The two advantages of the horizontal system are 23  and 24  In comparison with the downflow system, the horizontal system is less effective.

A. it requires several beds
B. it is easier to construct
C. it builds on a gradient
D. it doesn’t need much attention

E. it produces less sludges
F. it isn’t always working
G. it needs deeper bed
H. it can deal with more heavily polluted water

Questions 25-26

8.    Choose two correct letters, from the following A, B, C, D or E. Write your answers in boxes 25—26 on your answer sheet. What are the TWO advantages of the natural water purification system mentioned in the passage: A. It uses micro-organisms B. It involves a low operating cost C. It prevents flooding. D. It is visually good-looking E. It can function in all climates

READING PASSAGE 1

You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.

The nature of Yawning

A. While fatigue, drowsiness or boredom easily bring on yawns, scientists are discovering there is more to yawning than most people think. Not much is known about why we yawn or if it serves any useful function. People have already learned that yawning can be infectious. “Contagious yawning” is the increase in likelihood that you will yawn after watching or hearing someone else yawn, but not much is known about the under-lying causes, and very little research has been done on the subject. However, scientists at the University of Albany, as well as the University of Leeds and the University of London have done some exploration.

B. It is commonly believed that people yawn as a result of being sleepy or tired because they need oxygen. However, the latest research shows that a yawn can help cool the brain and help it work more effectively, which is quite different from the popular belief that yawning promotes sleep and is a sign of tiredness. Dr. Andrew Gallup and his colleagues at the University of Albany in New York State said their experiments on 44 students showed that raising or lowering oxygen and carbon dioxide levels in the blood did not produce that reaction. In the study participants were shown videos of people laughing and yawning, and researchers counted how many times the volunteers responded to the “contagious yawns”. The researchers found that those who breathed through the nose rather than the mouth were less likely to yawn when watching a video of other people yawning. The same effect was found among those who held a cool pack to their forehead, whereas those who held a warm pack yawned while watching the video. Since yawning occurs when brain temperature rises, sending cool blood to the brain serves to maintain the best levels of mental efficiency.

C. Yawning is universal to humans and many animals. Cats, dogs and fish yawn just like humans do, but they yawn spontaneously. Only humans and chimpanzees, our closest relatives in the animal kingdom, have shown definite contagious yawning. Though much of yawning is due to suggestibility, sometimes people do not need to actually see a person yawn to involuntarily yawn themselves: hearing someone yawning or even reading about yawning can cause the same reaction.

D. However, contagious yawning goes beyond mere suggestibility. Recent studies show that contagious yawning is also related to our predisposition toward empathy— the ability to understand and connect with others’ emotional states. So empathy is important, sure, but how could it possibly be related to contagious yawning? Leave it up to psychologists at Leeds University in England to answer that. In their study, researchers selected 40 psychology students and 40 engineering students. Generally, psychology students are more likely to feel empathy for others, while engineering students are thought to be concerned with objects and science. Each student was made to wait individually in a waiting room, along with an undercover assistant who yawned 10 times in as many minutes. The students were then administered an emotional quotient test: students were shown 40 images of eyes and asked what emotion each one displayed. The results of the test support the idea that contagious yawning is linked to empathy. The psychology students—whose future profession requires them to focus on others—yawned contagiously an average of 5.5 times in the waiting room and scored 28 out of 40 on the emotional test. The engineering students—who tend to focus on things like numbers and systems—yawned an average of 1.5 times and scored 25.5 out of 40 on the subsequent test. The difference doesn’t sound like much, but researchers consider it significant. Strangely enough, women, who are generally considered more emotionally attuned, didn’t score any higher than men.

E. Another study, led by Atsushi Senju, a cognitive researcher at the University of London, also sought to answer that question. People with autism disorder are considered to be developmentally impaired emotionally. Autistics have trouble connecting with others and find it difficult to feel empathy. Since autistics have difficulty feeling empathy, then they shouldn’t be susceptible to contagious yawning. To find out, Senju and his colleagues placed 49 kids aged 7 to 15 in a room with a television. 24 of the test subjects had been diagnosed with autism spectrum disorder, the other 25 were non-autistic kids. The test subjects were shown short clips of people yawning as well as clips of people opening their mouths but not yawning. While the kids with autism had the same lack of reaction to both kinds of clips, the non-autistic kids yawned more after the clips of people yawning.

F. There also have been studies that suggest yawning, especially psychological “contagious” yawning, may have developed as a way of keeping a group of animals alert and bonding members of a group into a more unit one. If an animal is drowsy or bored, it may not be as alert as it should to be prepared to spring into action and its yawning is practically saying, “Hey, I need some rest, you stay awake”. Therefore, a contagious yawn could be an instinctual reaction to a signal from one member of the herd reminding the others to stay alert when danger comes. So the theory suggests evidence that yawning comes from the evolution of early humans to be ready to physically exert themselves at any given moment.

Question 1 - 5

Read paragraphs A—F. Which paragraph contains the following information? NB You may use any letter more than once.

Target

1. Humans’ imaginations can cause yawning.

2. Research shows that yawning is closely related to occupations.

3. An overview of the latest research in yawning.

4. Yawning is used to regulate brain temperature.

5. Scientists discovered some evidence disproving the early understanding of yawning.

Characteristics

A

B

C

D

E

F

1:  

2:  

3:  

4:  

5:  

Questions 6 - 9

Match each of the following research results with the university which it comes from NB You may use any letter more than once.

Target

6. There is no gender difference in the cause of yawning.

7. People with certain disorders are less likely to be affected by other people yawning.

8. Yawning is associated with the way people breathe.

9. People who are trained to feel empathy for others are more likely to yawn than those who are untrained.

Characteristics

A. University of Albany

B. University of Leeds

C. University of London

6:  

7:  

8:  

9:  

Questions 10 - 13

Another theory shows that yawning is used for 10   individuals into a tighter social unit. Alternatively, yawning can help increase alertness of group members in case 11   is close. For example, yawning signals that a member of the group needs some 12  and requires the others to stay aware of the surrounding situation. This theory proves that yawning is only a spontaneous behaviour resulting from some part of a simple 13   system in early humans.

exercise 7 : reorder

1. favorite / maths / are / and / science / my / subjects /.

2. they/ have / do / on / vietnamese / monday/?

3. what / do / tuesday / have / lessons /you / on /?

4 english /nga / times / and / a / music / once / a / week / has / three / week / .

5 . do / how / maths / nam and hoa / often / have / ?

6 . they / work / not / on / do / sarturday / go / and / to / sunday /?

7 i / because / am / i / to / at / english / have / home / study / my / lesson / .