1.he was working on a project.
наверное вы уже знаете, это past continuous.
если мы говорим про первое лицо, то есть:
"I, she, he, it" то мы пишем "was*, и добавляем окончание -ing к глаголу.
а если " we, you, they ", то пишем "were" и также
добавляем окончание -ing к глаголу.
2.When Sue came back home, her sister had already mopped the floor.
3.While John was having lunch, Jane was making phone calls.
4.Ann couldn't wake up late because she arranged to go out with her friends.
5.He asked Helen to go to the cinema with her, but she refused.
6.Stella was very angry because she had been waiting Robert for an hour.
7.Sally was rather tired as she worked on the computer all morning.
1) Наши инженеры проверили эту машину в движении.
В отрицательном будет: Our engineers didn't test this machinery in the motion.
2) Теперь работники устанавливают новый трек.
В отрицательном будет: Now the workers aren't laying down the new track.