Выберите правильный вариант: the eiffel tower (1) … by millions of tourists every year. it (2) … in 1899 for the paris exposition. since that time it … (3) the most famous place in paris. i never (4) … to france so if i (5) … to visit paris i definitely (6) … to climb on the top of it. 1. 1) is visit; 2) visits; 3) is visited; 4) had been visited. 2. 1) was built; 2) was build; 3) had been built; 4) has been built. 3. 1) became; 2) has become; 3) have become; 4) becomes. 4. 1) has never been; 2) have been never; 3) have never been; 4) was. 5. 1) happens; 2) am happened; 3) am happening; 4) happen. 6. 1) will try; 2) try; 3) have tried; 4) have been trying.

Simultaneously with the creation of private copies of viruses can harm: to destroy, to damage, to steal data, to reduce or completely prevent further operation of the computer operating system. 2. harmless viruses do not interfere with the operation of the computer, but reduce the amount of free ram and memory on the disc; the actions of such viruses appear in any graphic or sound effects. 3. the most common kind of “trojans” is widely known programs use (editors, games, translators), which are embedded in the so-called “logic bombs” that are triggered in case of occurrence of some event. 4. compared with viruses trojan horses are not widely spread due to quite simple reasons, they either destroy themselves together with other data on the disk, or unmask their presence and destroyed by the user. 5. known viruses are invisible which are very difficult to detect and neutralize, as they intercept treatment operating system to the affected files or sectors of disks and substitute uncontaminated areas of the disk.