passive voice

Greenhouse gases ................................ by factories every day.

• are produced

• is produced

• was produced

• were produced

Avalanches ......................................... by careless skiers.

• are sometimes caused

• were sometimes cause

• was sometimes caused

• is sometimes caused

The window ............................... by Mark yesterday.

• is broken

• was broken

• were broken

• are broken

Rubbish ............................... to the oceans by people.

• is thrown away

• were thrown away

• are thrown away

• was throw away

Our environment ......................................... all the time.

• are polluted

• were polluted

• was pollute

• is polluted

Susan ............................ to the party by Tom two days ago.

• were invited

• was invited

• are invited

• is invited

Earthquakes ........................................... by people.

• are sometimes caused

• is sometimes caused

• was sometimes cause

• were sometimes cause

The letter ............................... by Mary last week.

• were written

• was written

• is wrote

• are written