Надо. определите в каждом из предложений видовременную форму и залог глагола-сказуемого. 1. before the experiment the substances are mixed in a large cup. 2.the latest surgical instruments were used during this unique operation. 3.the new engine is being tested in the laboratory. 4. its a long time since i have visited that town. 5. the street has been widened. 6. i have not made my plants yet.
простое, пассивный залог (past simple, passive voice)
3. is being tested - настоящее длительное, пассивный залог (present continuous, passive voice)
4. is - настоящее простое (present simple), have visited - настоящее завершённое, залог активный (present perfect, active voice)
5. has been widened - настоящее завершённое, пассивный залог (present perfect, passive voice)
6. have not made - настоящее завершённое, активный залог (present perfect, active voice)