Read the following passage and mark the letter A, B, C, or D to indicate the correct word to each of the blanks from 36 to 45.
The volume of traffic in many cities in the world today continues to expand. This (36) ______ many problems including serious air pollution, lengthy delays, and the greater risk (37) ______ accidents. Clearly, something must be done, but it is often difficult to persuade people to change their habits and leave their cars at home.
One possible (38) ______ is to make it more expensive for people to use their cars by increasing charges for parking and bringing in tougher fines for anyone who (39) ______ the law. In addition, drivers could be required to pay for using particular routes at different times of the day. This system(40) ______ as ‘road pricing’, is already being introduced in a number of cities, using a special electronic card (41) ______ to windscreen of the car.
Another way of (42) ______ with the problem is to provide cheap parking on the outskirts of the city, and strictly control the number of vehicles allowed into the centre. Drivers and their passengers then use a special bus service for the (43) ______ stage of their journey.
Of course, the most important (44) ______ is to provide good public transport. However, to get people to give up the comfort of their cars, public transport must be felt to be reliable, convenient and comfortable with fares (45) ______ at an acceptable level.
Read the following passage and mark the letler A, B, C, or D to indicate the correct answer to each of the questions .
Broad-tailed hummingbirds often nest in quaking, slender deciduous trees with smooth, gray-green bark found in the Colorado Rockies of the western United States. After flying some 2,000 kilometres north from where they have wintered in Mexico, the hummingbirds need six weeks to build a nest, incubate their eggs, and raised the chicks. A second nest is feasible only if the first fails early in the season. Quality, not quantity, is what counts in hummingbird reproduction.
A nest on the lowest intact branch of an aspen will give a hummingbird a good view, a clear flight patch, and protection for her young. Male hummingbirds claim feeding territories in open meadows where, from late May through June they mate with females coming to feed but take no part in nesting. Thus when the hen is away to feed, the nest is unguarded. While the smooth bark of the aspen trunk generally offers a poor grip for the claws of a hungry squirrel or weasel, aerial attacks, from a hawk, owl, or gray jay, are more likely.
The choice of where to build the nest is based not only on the branch itself but also on what hangs over it. A crooked deformity in the nest branch, a second, unusually close branch overhead. or proximity to part of a trunk bowed by a past ice storm are features that provide shelter and make for an attractive nest site. Scarcely larger than a halved golf ball, the nest is painstaking constructed of spider webs and plant down, decorated and camouflaged outside with paper-like bits of aspen bark held together with more strands of spider silk. By early June it will hold two pea-sized eggs, which each weigh one-seventh of the mother's weight, and in sixteen to nineteen days, two chicks.
Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions.
The word laser was coined as an acronym for Light Amplification by the Stimulated Emission of Radiation. Ordinary light, from the Sun or a light bulb, is emitted spontaneously, when atoms or molecules get rid of excess energy by themselves, without any outside intervention. Stimulated emission is different because it occurs when an atom or molecule holding onto excess energy has been stimulated to emit it as light.
Albert Einstein was the first to suggest thc existence of stimulated emission in a paper published in 1917. However, for many years physicists thought that atoms and molecules always were much more likely to emit light spontancously and that stimulated emission thus always would be much weaker. It was not until after the Second World War that physicists began trying to make stimulated emission dominate. They sought ways by which, one atom or molecule could stimulate many others to emit light, amplifying it to much higher powers.
The first to succeed was Charles H. Townes, then at Columbia University in New York. Instead of working with light, however, he worked with microwaves, which have a much longer wavelength, and built a device he called a “maser”, for Microwave Amplification by the Stimulated Emission of Radiation. Although he thought of the key idea in 1951, the first maser was not compleled until a couple of years later. Before long, many other physicists were building masers and trying to discover how to produce stimulated emission at even shorter wavelengths.
The key concepts emerged about 1957. Townes and Arthur Schawlow, then at Bell Telephone Laboratories, wrote a long paper outlining the conditions needed to amplify stimulated emission of visible light waves. At about the same time, similar ideas crystallized in the mind of Gordon Gould, then a 37-year-old graduate student at Columbia, who wrote them down in a series of notebooks. Townes and Schawlovs published their ideas in a scientific journal, Physical Review Letters, but Gould files a patent application. Three decades later, people still argue about who deserves the credit for the concept of the laser.