Turn from Active into Passive. Omit the agent where it can be omitted. 1. They kill elephants for ivory...

1. Elephants are killed for ivory.
2. The "Iliad" was written by Homer.
3. A lot of trees are chopped down every year.
4. New measures against crime will be introduced by the government.
5. Ann's house has been burgled.
6. I was offered a cup of tea by her.
7. Passports are checked at Passport Control.
8. The cathedral is visited by a million people every year.
9. Mike's bicycle has been stolen.

When converting sentences from active to passive voice, the object of the active sentence becomes the subject of the passive sentence. The focus shifts from who is performing the action (the agent) to who or what is receiving the action. The agent is omitted if it is either unknown or not important. Here are the conversions for the given sentences:

1. Homer wrote the "Iliad."

   • Passive: The "Iliad" was written by Homer. (In this sentence, the agent "Homer" is important as it identifies the author, so it is not omitted.)

2. People chop down a lot of trees every year.

   • Passive: A lot of trees are chopped down every year. (The agent "people" is general and not specified, so it is omitted.)

3. The government will introduce new measures against crime.

   • Passive: New measures against crime will be introduced by the government. (The agent "the government" is specific and significant, so it is not omitted.)

4. Someone has burgled Ann's house.

   • Passive: Ann's house has been burgled. (The agent "someone" is unknown and not important, so it is omitted.)

5. She offered me a cup of tea.

   • Passive: I was offered a cup of tea. (The agent "she" can be omitted if the focus is on the action of offering.)

6. They check passports at Passport Control.

   • Passive: Passports are checked at Passport Control. (The agent "they" is general and not specified, so it is omitted.)

7. A million people visit the cathedral every year.

   • Passive: The cathedral is visited by a million people every year. (The agent "a million people" is specific and notable, so it is not omitted.)

8. Someone has stolen Mike's bicycle.

   • Passive: Mike's bicycle has been stolen. (The agent "someone" is unknown and not important, so it is omitted.)

In summary, when converting from active to passive voice, the object of the active sentence becomes the subject of the passive sentence, and the verb form changes to accommodate the new subject. The agent is often omitted unless it is important for context or clarity.