PRACTICE TEST
TOEFL PBT 1 part 4
READING 1
Just as
optical fibers have transformed communication, they are also revolutionizing
medicine. These ultra- thin, flexible fibers have opened a window into the
living tissues of the body. By inserting optical fibers through natural
openings or small incisions and threading them along the body’s established pathways,
physicians can look into the lungs, intestines, heart, and other areas that
were formerly inaccessible to them.
The basic
fiber-optics system is called a fiberscope, which consists of two bundles of
fibers. One, the illuminating bundle, carries light to the tissues. It is
coupled to a high-intensity light source. Light enters the cores of the high-purity
silicon glass and travels along the fibers. A lens at the end of the bundle
collects the light and focuses it into the other bundle, the imagining bundle.
Each fiber in the bundle transmits only a tiny fraction of the total image. The
reconstructed image can be viewed through an eyepiece or displayed on a
television screen. During the last five years, improved methods of fabricating
optical fibers have led to a reduction in fiberscope diameter and an increase
in the number of fibers, which in turn has increased resolution.
Optical
fibers can also be used to deliver laser light. By use of laser beams,
physicians can perform surgery inside the body, sometimes eliminating the need
for invasive procedures in which healthy tissue must be cut through to reach
the site of disease. Many of these procedures do not require anesthesia and
can be performed in a physician’s office. These techniques have reduced the risk
and the cost of medical care.
1. What
is the main subject of the passage?
a. A
revolution in communication c. New surgical techniques
b. The
invention of optical fibers d.
The role
2. In
line 2, the author uses the expression have
opened a window to indicate that the use of optical fibers.
a. Has
enabled scientists to make amazing discoveries
b. Sometimes
requires a surgical incision.
c. Allows
doctors to see inside the body without major surgery.
d. Has
been unknown to the general public until quite recently.
3. Which
of the following is closest in meaning to the word formerly in line 4?
a. Previously
c.
Usually
b. Completely d.
Theoretically
4. The
word them in line 4 refers to
a. optical
fibers c.
other areas of the body
b. pathways d.
physicians
5. According
to the passage, what is the purpose of the illuminating bundle in a fiberscope
a. To
carry light into the body c.
To reconstruct images
b. To
collect and focus light d.
To perform surgery inside the body
6. Which
of the following is the closest in meanings to the word cores in line 6?
a. Tips c.
Clusters
b. Centers d.
Lines
7. According
to the passage, how do the fiberscopes used today differ from those used five
years ago?
a. They
use brighter lights. c.
They contain more fibers
b. They
are longer. d.
They are larger in diameter
8. The
word resolution in line 11 is closest
in meaning to which of the following?
a. Strength c.
Inconvenience
b. Sharpness d.
Efficiency
9. Which
of the following is NOT mentioned by the author as one of the advantages of
laser surgery techniques?
a. They
can be performed in a physician’s office
b. They
are safer than conventional surgery.
c. They
can often be performed without anaesthesia.
d. They
are relatively easy to teach ti physicians
ANSWER KEY
1. D
2. C
3. A
4. D
5. A
6. B
7. C
8. B
9. D
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