Simple Active - he uses - he measures - he used - he could call - they named, Simple Passive - he can be called - they were named, Progressive Active - he is using, Perfect Active - he has measured - he has used, Perfect Passive - they have been named.1. They … a new reagent in their experiment. b) did not use 2. We … this metal with sulphuric acid to obtain hydrogen yesterday. a) did not treat 3. The researchers … new substances last week. a) did not obtain 4. Soon we shall receive a new laboratory equipment…? a) shall not we 5. The experiment was very difficult…? b) wasn’t it 6. … a concentrated solution contain a large amount of a dissolved substance? d) does