Времена Past Английский яз тест,кто знает решение?

Past Time Revision Test

1) Only the framework of the building (stand) after the fire last month.
2) They recently (decide) to locate a new construction site 30 miles from the city center.
3) The survey just (examine) the impact of current modernization within the construction industry.
4) We (clean) the office when the boss came.
5) We already (clean) the office when the boss came.
6) We (clean) the office for 2 hours when the boss came.
7) This company (construct) 3 houses in 2020.
8) The designer (use) a computer in the office at 5 o’clock yesterday.
9) They (build) a new hospital before I came to that town.
10) V. Shukhov (bring) a lot of innovations to the construction of may bridges and buildings.
11) After the exhibition had closed, we (go) home.
12) Vladimir G. Shukhov (be) a great Russian engineer, scientist and architect.
13) I (drive) to work yesterday.
14) He (work) as a chief engineer before he started his own business.
15) They (conduct) an experiment on the construction site at 9 o’clock yesterday.
нужно определить действие PAST,Раскрыть скобки как будет правильно писаться и под каждым преложением указать действие,Буду благодарен за помощь,Англичане спасайте.