EXERCISE 22PART 1: READINGThe first

EXERCISE 22
PART 1: READING
The first two decades of this century were dominated by the microbe hunters. These hunters had tracked down one after another of the microbes responsible for the most
dreaded scourges of many centuries ; tuberculosis, cholera, diphtheria. But there
remained
Line some terrible diseases for which no microbe could be incriminated : scurvy, pellagra,
(5) rickets, beriberi. Then it was discovered that these diseases were caused by the lack of
vitamins, a trace substance in the diet. The diseases could be prevented or cured by
consuming foods that contained the vitamins. And so in the decades of the 1920's and
1930's, nutrition became a science and the vitamin hunters replaced the microbe
hunters.
In the 1940's and 1950's, biochemists strived to learn why each of the vitamins was
(10) essential for health. They discovered that key enzymes in metabolism depend on one or
another of the vitamins as coenzymes to perform the chemistry that provides cells with
energy for growth and function. Now, these enzymes hunters occupied center stage.
You are aware that the enzyme hunters have been replaced by a new breed of hunters
who are tracking genes ― the blueprints for each of the enzymes ― and are
discovering
(15) the defective genes that cause inherited diseases ― diabetes, cystic fibrosis. These gene
hunters, or genetic engineers, use recombinant DNA technology to identify and clone
genes and introduce them into bacterial cells and plants to create factories for the
massive production of hormones and vaccines for medicine and for better crops
for agriculture. Biotechnology has become a multibillion-dollar industry.
(20) In view of the inexorable progress in science, we can expect that the gene hunters
will be replaced in the spotlight. When and by whom? Which kind of hunter will
dominate
the scene in the last decade of our waning century and in the early decades of the next ?
I wonder whether the hunters who will occupy the spotlight will be neurobiologists
who apply the techniques of the enzyme and gene hunters to the functions of the brain.
(25) What to call them? The head hunters. I will return to them later.
24. What is the main topic of the passage?
(A) The microbe hunters
(B) The potential of genetic engineering
(C) The progress of modern medical research
(D) The discovery of enzymes
25. Which of the following can be cured by a change in diet?
(A) Tuberculosis
(B) Cholera
(C) Cystic fibrosis
(D) Pellagra
26. How do vitamins influence health?
(A) They are necessary for some enzymes to function.
(B) They protect the body from microbes.
(C) They keep food from spoiling.
(D) They are broken down by cells to produce energy
27. In the third paragraph, the author compares cells that have been
genetically altered by biotechnicians to
(A) gardens
(B) factories
(C) hunters
(D) spotlights
28. The phrase“occupy the spotlight”in line 23 is closest in meaning to
(A) receive the most attention
(B) go the furthest
(C) conquer territory
(D) lighten the load
29. The author implies that the most important medical research topic of the
future will be
(A) the functions of the brain
(B) inherited diseases
(C) the operation of vitamins
(D) the structure of genes
In the mid-nineteenth century, the United States had tremendous natural resources
that could be exploited in order to develop heavy industry. Most of the raw materials
that are valuable in the manufacture of machinery, transportation facilities, and
consumer
Line goods lay ready to be worked into wealth. Iron, coal, and oil ― the basic ingredients of
(5) industrial growth ― were plentiful and needed only the application of technical
expertise,
organizational skill, and labor.
One crucial development in this movement toward industrialization was the growth
of the railroads. The railway network expanded rapidly until the railroad map of the
United States looked like a spider's web, with the steel filaments connecting all
important
(10) sources of raw materials, their places of manufacture, and their centers of distribution.
The railroads contributed to the industrial growth not only by connecting these major
centers, but also by themselves consuming enormous amounts of fuel, iron, and coal.
Many factors influenced emerging modes of production. For example, machine
tools, the tools used to make goods, were steadily improved in the latter part of the
(15) nineteenth century ― always with an eye to speedier production and lower unit costs.
The products of the factories were rapidly absorbed by the growing cities that sheltered
the workers and the distributors. The increased urban population was nourished by the
increased farm production that, in turn, was made more productive by the use of the
new farm machinery. American agricultural production kept up with the urban demand
(20) and still had surpluses for sale to the industrial centers of Europe.
The labor that ran the factories and built the railways was recruited in part from
American farm areas where