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.
2. What a wonderful picture you have painted!
3. The boys have helped their father to wash the car. The car is clean.
4. The writer has finished a new story. We can read it.
5. I have joined a sports club. Now I am a sportsman.