1. Vintor Ceft made (past simp act) many efforts to build and standardize the internet. 2. Our laboratory are carrying (pres cont act) on a very important experiment now. 3. The group of scientists have already carried (pres perf act) out important research. 4. This phenomenon is described (pres simp pass) in the literature. 5. The Internet techology was created (past simp pass) by Vinton Cerf in early 1970`s. 6. An interesting and very important experiment was being made (past cont pass) at that hour. 7. The conductance between the plates may be affected (pres simp act) by other factors. 8. Modern computers are more and more being relied (pres cont pass) on by mathematics as well as other sciences.