1. Geometric progression is a series of numbers, in which each is multiplied or divided by a fixed number to produce the next, for example 1, 3, 9, 27, 81.
2. Backup copy is a copy of a file, program, etc. that is applied if the original is lost or damaged.
3. This software enables companies to monitor employees' Internet use.
4. Information can be processed, exchanged between the windows on the screen or printed in the required sequence.
5. The entertainment industry is a large branch of the economy, which is engaged in making movies, television programmes, music records to entertain people.
6. For security reasons, video cameras were installed at the school entrance.
7. Data and messages can be transmitted from one computer to another by means of telephone lines, microwave links [радиорелейная линия], communications satellites, or other telecommunications equipment.
8. The government took new measures against illegal using and coping pirated software.
9. The software converts files from Macintosh format to Windows format.
10. A floppy disk usually holds 1.44 megabytes of data, which is equal to about 1,400,000 keyboard characters. At this storage capacity, a single disk can store a document about 700 pages long, with 2000 characters per page.
11. Frequency is the speed at which a sound or electromagnetic wave vibrates, i.e. moves up and down.
12. The screen size of monitors is measured by the distance from one corner of the display to the diagonally opposite corner.
13. Customers can select from thousands of products, which are represented in the online catalogues.
14. In the electronic game Tetris, players must manipulate geometric shapes that fall from the top of the screen. The aim is to create solid rows.
15. Mainframe is a large powerful computer, usually the centre of a network that is shared by many users.