12. The chief engineer was instructing all the workers.of the plant
=> All the workers of the plant were being instructed by the chief engineer.
13. The students were learning English at 8 am yesterday
=> English was being learned by the students at 8 am yesterday.
14. What were you watching between 8 and 9 o'clock last night?
=> What was being watched by you between 8 and 9 o'clock last night?
15. Was Nam eating the Fried Chinese Rice when you arrived?
=> Was the Fried Chinese Rice being eaten by Nam when you arrived?
16. Were the scouts collecting the broken glass for recycling at tis time last month?
=> Was the broken glass being collected by the scouts for recycling at tis time last month?
17. Which sport were you playing at 4 o'clock yesterday afternoon?
=> Which was sport being played by you at 4 o'clock yesterday afternoon?
18. They weren't planting rubber trees in the forest at 9 am last Saturday
=> Rubber trees in the forest weren't planted by them at 9 am last Saturday.
19. Was your mother making tea at 10 o'clock last night?
Was tea made by your mother at 10 o'clock last night?
20. Arthur was teaching vocabulary from 7 to 10 last night.
=> Vocablulary was being taught by Arthur from 7 to 10 last night.
