In Death Valley, California, one of the hottest, most arid places in North America, there is much salt, and salt can damage rocks impressively. Inhabitants of areas elsewhere, where streets and highways are salted to control ice, are familiar with the resulting rust and deterioration on cars. That attests to the chemically corrosive nature of salt, but it is not the way salt destroys rocks. Salt breaks rocks apart principally by a process called crystal prying and wedging. This happens not by soaking the rocks in salt water, but by moistening their bottoms with salt water. Such conditions exist in many areas along the eastern edge of central Death Valley. There, salty water rises from the groundwater table by capillary action through tiny spaces in sediment until it reaches the surface.

Most stones have capillary passages that suck salt water from the wet ground. Death Valley provides an ultra-dry atmosphere and high daily temperatures, which promote evaporation and the formation of salt crystals along the cracks or other openings within stones. These crystals grow as long as salt water is available. Like tree roots breaking up a sidewalk, the growing crystals exert pressure on the rock and eventually pry the rock apart along planes of weakness, such as banding in metamorphic rocks, bedding in sedimentary rocks, or preexisting or incipient fractions, and along boundaries between individual mineral crystals or grains. Besides crystal growth, the expansion of halite crystals (the same as everyday table salt) by heating and of sulfates and similar salts by hydration can contribute additional stresses. A rock durable enough to have withstood natural condition for a very long time in other areas could probably be shattered into small pieces by salt weathering within a few generations.

The dominant salt in Death Valley is halite, or sodium chloride, but other salts, mostly carbonates and sulfates, also cause prying and wedging, as does ordinary ice. Weathering by a variety of salts, though often subtle, is a worldwide phenomenon. Not restricted to arid regions, intense salt weathering occurs mostly in salt-rich places like the seashore, near the large saline lakes in the Dry Valleys of Antarctica, and in desert sections of Australia, New Zealand, and central Asia.

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John is having a clown birthday party. The clown is appearing. He always loves watching the clown. He is looking happy.

Lately, I ____ about changing my career because I ____ dissatisfied with the conditions at my company.

After the concert, everyone had to ____ through the thick snow.

They were walking on tiptoe _______ the Director's room.

Read the following passage and then choose the most suitable word or phrase for each space.

The money that some professional sportsmen earn shouldn't impress anyone when you take into (1) __ the fact that only a few of them manage to attain immortality and everlasting fame. And once they reach their (2) __ and display their talent at their best, they are fully conscious that their brilliant careers won't last forever. They live under a constant pressure of being (3) ____ and subsequently replaced by someone who is younger, faster and more accomplished. For that reason, objectives like retirement benefits and pensions are (4)____ great concern to all professional athletes. Some of the retired competitors go as far as to organize strikes and rallies to voice their protest against any policy unresponsive to their demand (5)_____ the younger professionals seek more upgrading solutions to the problem as more and more of them attach a proper significance to (6)___ a solid education, even at university level. Such an approach should help them find interesting and well-paid jobs (7)____ their sports career is over. A completely new strategy has been devised by the schools priding themselves (8)_____ supporting their own teams. Their authorities insist that the sports clubs members achieve high academic standards or else they are debarred from partaking in certain sports events, which may lead to further disruption in their professional careers. By these practical and most effective (9)___, combining education with sports activity, the (10)___ of the professional athlete as being brainless and unintelligent may eventually be changing to the sportsmen's benefit.

My car broke down yesterday, so I ____ catch a taxi to the office.

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Most human diets contain between 10 and 15 percent of their total calories as protein. The rest of the dietary energy comes from carbohydrates, fats, and in some people, alcohol. The proportion of calories from fats varies from 10 percent in poor communities to 40 percent or more in rich communities.

In addition to providing energy, fats have several other functions in the body. The fat-soluble vitamins, A, D, E, and K, are dissolved in fats, as their name implies. Good sources of these vitamins have high oil or fat content, and the vitamins are stored in the body’s fatty tissues. In the diet, fats cause food to remain longer in the stomach, thus increasing the feeling of fullness for some time after a meal is eaten. Fats add variety, taste, and texture to foods, which accounts for the popularity of fried foods. Fatty deposits in the body have an insulating and protective value. The curves of the human female body are due mostly to strategically located fat deposits.

Whether a certain amount of fat in the diet is essential to human health is not definitely known. When rats are fed a fat-free diet, their growth eventually ceases, their skin becomes inflamed and scaly, and their reproductive systems are damaged. Two fatty acids, linoleic and arachidonic acids, prevent these abnormalities and hence are called essential fatty acids. They also are required by a number of other animals, but their roles in human beings are debatable. Most nutritionists consider linoleic fatty acid an essential nutrient for humans.

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Could you close the window? There is a bit of a _____.

Indicate the word(s) OPPOSITE in meaning to the underlined word(s):

I prefer reading fictional stories to hearing about real events.

We were _______ by the officers' decision to divert the whole traffic from the main route.