Exercise 8. Put each of the following words or phrases in its correct place in the passage below.
| · relies · information · charts · telescope · launched · adjustments · operate |
The Hubble telescope
The Hubble telescope was …1… into space with great fanfare on April 25, 1990. Although there are many powerful telescopes at various locations on Earth, the Hubble …2… was expected to be able to provide considerably better …3… because it would be able to …4… from the vacuum of space, without interference from the Earth's atmosphere. By launching the Hubble telescope into space, NASA was, in essence, placing an observatory above the Earth's atmosphere.
Unfortunately, the Hubble telescope was initially delayed in relaying its first pictures back from space due to a simple mathematical miscalculation. The Hubble telescope …5… upon certain stars to orient its observations, and astronomers working on the pointing instructions for the telescope used …6… created in 1950, with adjustments for the movements of the stars in the ensuing period. In making these …7…, however, astronomers added the amount of the adjustment rather than subtracting it – a simple checkbook-balancing error. The adjustment was a change of only half a degree, but by adding half a degree rather than subtracting it, the telescope's aim was misdirected by millions of miles.
Exercise 9. Put each of the following words or phrases in its correct place in the passage below.
| · printer · projected · conductor · light · xerography · toner · material |
Xerography
One more familiar use of electrochemistry that has made its way into the mainstream is …1…, a process for replicating documents that is dependent on photoconductive materials. A photoconductive …2… is an insulator in the dark but becomes a …3… when exposed to bright light. When a photocopy is being made, an image of a document is …4… onto the surface of a rotating drum, and bright …5… causes the photoconductive material on the surface of the drum to become conductive.
As a result of the conductivity, the drum loses its charge in the lighted areas, and …6… (small grains to which dry ink adheres) attaches itself only to the darker parts of the image. The grains are then carried to a sheet of paper and fused with heat. When a laser …7… is used, the image is projected by means of a laser beam, which creates a brighter light and a greater contrast between lighter and darker areas and therefore results in sharper printed images.
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Exercise 10. Read the text and put the sentences below into the correct place.
Uranium
1. Uranium, a radioactive metal named after the planet Uranus, is a primary source of energy in nuclear power plants and certain nuclear weapons. It occurs naturally in three different isotopes, which differ in their facility in undergoing nuclear fission.
2. [1]The three naturally occurring isotopes of uranium are U-234, U-235, and U-238. [2]Each of these isotopes has the same atomic number of 92, which is the number of protons in the nucleus. [3]However, each has a different number of neutrons and thus has a different atomic mass, which is the sum of the number of protons and neutrons. [4]
3. Of these three naturally occurring isotopes of uranium, U-238 is by far the most common, while U-235 is the most capable of undergoing nuclear fission. [5] More than 99 percent of all naturally occurring uranium is U-238, while U-234 and U-235 each makes up less than 1 percent. [6] Nuclear fission can occur when a U-235 nucleus is struck by a neutron, and the nucleus splits, releasing energy and releasing two or more neutrons. [7] However, nuclear fission rarely involves a U-238 or a U-234 nucleus because it is unusual for either of these nuclei to break apart when struck by a neutron. [8]
a) Look at the four figures [1–4] that indicate where the following sentence can be added to the second paragraph of the passage:
U-234 has 92 protons and 142 neutrons for an atomic mass of 234, U-235 has 92 protons and 143 neutrons for a total of 235, and U-238 has 92 protons and 146 neutrons for a total of 238.
b) Look at the four figure [5–8] that indicate where the following sentence can be added to the third paragraph of the passage.
These neutrons can create a chain reaction by causing other U-235 nuclei to break up.
Exercise 11. Scan the text and find out the necessary information in order to answer the questions below.
Real Bill Gates
It's hard to believe that the first personal computer, the prototype of the computer now found in homes and offices around the world, was developed less than thirty years ago. The software for that machine was developed by William Henry Gates.
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Bill was born in 1955 in Seattle. He became interested in computers when be was 13. His parents sent him to the elite, private school, where he learned computer language. He placed within the top ten in the nation at the exam. Then Gates went to Harvard. Later William returned to Seattle where he established the Microsoft Company in 1975.
It employed only three workers at first. Microsoft developed software for established American companies like General Electric, City Bank and IBM. In 1981 IBM began selling a personal computer that used Microsoft products as part of its operating system. By then Microsoft had 129 workers.
Gates married Melinda French, in 1994. She graduated from Duke University with computer science and business degrees. Like Gates, she is smart and independent. Their daughter, Jennifer, was born in April 1996. "I used to think I wouldn't be all that interested in the baby until she could talk", says Gales. "But I'm totally into it now".
Gates runs his company mainly through three methods. Day and night he looks through e-mail messages; every month or so he meets with top management group; and most important 70 percent of his schedule, he holds two or three small meetings a day with team working on company products. For him the competition is sport.
Thanks to the success of his company, William Gates has earned a personal fortune of about 7 billion dollars. He is planning to give away 95 per cent of his wealth on charity. Gates has already given lots of money on some projects.
Today four out of five of the world's personal computers run on Microsoft software, on what is now called Windows. Windows system makes it much easier to use a computer. It's through the Windows system that we may access to the Internet, the global computer network.
Answer the questions.
1. Where did Bill Gates receive his education?
2. How did Microsoft develop?
3. Who make his family?
4. What are his rules by which he runs his company?
5. Has charity become his main focus?
PART 4. TEST YOURSELF
Variant 1
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