Dust generated by compressed air （bailing airflow) flushing the drill cuttings from the hole being drilled.

A、Wet suppression

B、Dry drill dust collection

C、Dry suppression

D、Wet drill dust collection

The fact that superior service can generate a competitive

advantage for a company does not mean that every attempt

at improving service will create such an advantage. Invest-

ments in service, like those in production and distribution,

(5) must be balanced against other types of investments on the

basis of direct, tangible benefits such as cost reduction and

increased revenues. If a company is already effectively on a

par with its competitors because it provides service that

avoids a damaging reputation and keeps customers from

(10) leaving at an unacceptable rate, then investment in higher

service levels may be wasted, since service is a deciding

factor for customers only in extreme situations.

This truth was not apparent to managers of one regional

bank, which failed to improve its competitive position

(15) despite its investment in reducing the time a customer had

to wait for a teller. The bank managers did not recognize

the level of customer inertia in the consumer banking

industry that arises from the inconvenience of switching

banks. Nor did they analyze their service improvement to

(20) determine whether it would attract new customers by pro-

ducing a new standard of service that would excite cus-

tomers or by proving difficult for competitors to copy. The

only merit of the improvement was that it could easily be

described to customers.

The primary purpose of the passage is to______

A．contrast possible outcomes of a type of business investment

B．suggest more careful evaluation of a type of business investment

C．illustrate various ways in which a type of business investment could fail to enhance revenues

D．trace the general problems of a company to a certain type of business investment

E．criticize the way in which managers tend to analyze the costs and benefits of business investments

Powering the great ongoing changes of our time is the rise of human creativity as the defining feature of economic life. Creativity has come to be valued, because new technologies, new industries and new wealth flow from it. And as a result, our lives and society have begun to echo with creative ideas. It is our commitment to creativity in its varied dimensions that forms the underlying spirit of our age.

Creativity is essential to the way we live and work today, and in many senses always has been. The big advances in standard of living—not to mention the big competitive advantages in the marketplace—always have come from "better recipes, not just more cooking." One might argue that's not strictly true. One might point out, for instance, that during the long period from the early days on the Industrial Revolution to modern times, much of the growth in productivity and material wealth in the industrial nations came not just from creative inventions like the steam engine, but from the widespread application of "cooking in quantity" business methods like massive division of labor, concentration of assets, vertical integration and economies of scale. But those methods themselves were creative developments.

听力原文： Unwanted sound or noise produced by airplanes, traffic, or industrial machinery, is considered a form. of pollution. Noise pollution is at its worst in densely polluted areas. It can cause hearing loss, stress, high blood pressure, sleep loss, distraction, and lost productivity.

Most humans can hear sounds between 20 and 20,000 hertz, while dogs can hear high-pitched sounds up to 50,000 hertz. While high frequency sounds tend to be more hazardous and more annoying to hearing than low frequency sounds, most noise pollution damage is related to the intensity of the sound. Measured in decibels, noise intensity can range from zero, the quietest sound the human ear can detect, to over 160 decibels. Conversation takes place at around 40 decibels, a subway train is about 80 decibels, and a rock concert is from 80 to 100 decibels. The intensity of a nearby jet taking off is about 100 decibels. The threshold for pain, tissue damage and potential hearing loss in humans is 120 decibels. Long lasting, high intensity sounds are the most damaging to hearing and produce the most stress in humans.

Solutions to noise pollution include adding insulation and sound proofing to doors, walls and ceilings; using ear protection, particularly in industrial working areas; planting vegetation to absorb and screen out noise pollution; and zoning urban areas to maintain a separation between residential areas and zones of excessive noise.

According to the passage, intense noise pollution may NOT cause

A．hearing loss.

B．high blood pressure.

C．lost productivity.

D．poor appetite.

After collecting the last Martian dust particle，the scientists have started to build up a portrail gallery of it．

A. Right

B. Wrong

C. Not mentioned

What do we learn about the untreated industrial chemical wastes from the passage?

A．They can conserve the normal biological action of rivers.

B．They all react with water to increase the acidity of rivers.

C．They make the water corrosive enough to destroy living organisms.

D．There are no rules for concentrations of unquestionably toxic chemicals of drinking water.

Why does the author use the word toll in discussing the iron industry in paragraph 3?

A．To show that the process of smelting iron was expensive

B．To illustrate the impact of forest fires on the iron industry

C．To point out that the iron industry had to pay high taxes

D．To emphasize that large areas of woodland were eliminated

What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth's Gravity(重力) pulls it. But every cloud is made of water droplets or ice crystals. Why doesn't rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly small. The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward displacement is zero, even though the droplets are in constant motion.

Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft(束) of sunlight. To the casual observer, dust seems to act in a totally random fashion, moving about wildly without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2,500 inch in diameter. (78)It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it does not fall out of moving air at all. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall form. the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain.

What is the main topic of the passage?

A．The mechanics of rain.

B．The climate of North America.

C．How gravity affects air current.

D．Types of clouds.