Active and Passive

Petroleum __________ a long time ago.

• is discovered

• was discovered

• was discovering

• discovered

Man __________ petroleum a long time ago.

• is discovered

• was discovered

• was discovering

• discovered

Petroleum _________ as a form of non-renewable energy.

• is used

• was used

• was using

• have been used

We _________ petroleum as a non-renewable form of energy.

• is used

• was used

• were using

• use

Rock formations __________ by geologists to find oil reserves.

• studied

• were studied

• are studying

• are studied

Geologists __________ rock formations to find oil reserves.

• study

• were studied

• studying

• are studied

The drilling crew _________ oil from the well.

• extracts

• are extracted

• extracting

• are extracting

Oil _________ from the well by the drilling crew.

• extracts

• is extracted

• extracting

• are extracting

The incident report __________ by the safety officer

• was preparing

• are prepared

• was prepared

• preparing

The safety officer _________ the incident report.

• was preparing

• prepared

• was prepared

• preparing