1. Error message [to appear –Present Indefinite Active] on a computer screen if you [to do –Present Perfect Active] something wrong or if the program cannot do what you [to want– Present Indefinite Active] it to do.
2. A few journalists [to allow –Past Perfect Passive] to view the film before it [to go –Past Indefinite Active] on general release.
3. The installed base (ïàðê óñòàíîâëåííîãî îáîðóäîâàíèÿ) [to be –Present Indefinite Active] the total number of computers that [to sell –Present Perfect Passive] and [to use /still – Present Continuous Passive] by customers.
4. Blaise Pascal [to be – Past Indefinite Active] one of the greatest scientists, the world [to know/ ever – Past Perfect Active].
5. Great improvements [to make – Present Perfect Passive] in the memory system of a computer since the invention of the first calculator.
6. Bill Gates was barely 20 years old but he [to run /already – Past Continuous Active] his own company.
7. E-mail [to become – Present Perfect Active] a key part of the communications networks of most modern offices.
8. Water [to get– Past Perfect Active] into the printer, and now it [to be –Past Indefinite Active] absolutely useless.
9. When free electrons [to pass – Present Continuous Active] through a conductor, an electric current [to generate –Present Continuous Passive].
10. The World Wide Web is the system on the Internet that [to allow– Present Indefinite Active] you to find and use information that [to store– Present Indefinite Passive] on computers all over the world.
11. The first electronic computer ENIAC [to develop –Past Continuous Passive] in the University of Pennsylvania from 1942 to 1946. It [to be –Past Indefinite Active] the fastest among the calculators, which [to design –Past Perfect Passive] by that time.
12. The computer automatically [to delete –Present Indefinite Active] any files that you [not / to save –Present Perfect Active].