The passive Ta Read the sentences. Which sentence is not in the passive? 1 ) The prizes are given to scientists.
2)An lg Nobel prize was won by two Japanese scientists.
)3 Johan Pettersson won the Chemistry lg Nobel prize.
4) These inventions won't be used much.
5)Lots of interesting research is being done at the monment.
6) Their machine has been taken.

1b Choose the correct alternative for each rule.
1)We use the passive when we are interested mainly action/person who does the action.
2 )We use the passive when it is/isn't obvious who does or did the action.
3) When we use the passive we always know/don't always know the person who does the action.

1 c Read the sentences in 1a again and answer the questions.
1 Which tense is each passive sentence written in?
2 What changes in different tenses of the passive - the verb to be or the past participle? 3 What preposition do we use to introduce the agent (the person or thing which does the action)?

Sentence 3 "Johan Pettersson won the Chemistry lg Nobel prize." is not in the passive voice.

Explanation:
In sentences 1, 2, 4, 5, and 6, the subject is receiving the action and the verb form indicates that the sentence is in the passive voice. In sentence 1, "The prizes are given to scientists," the prizes are the subject, and they are being given to scientists. In sentence 2, "An lg Nobel prize was won by two Japanese scientists," the lg Nobel prize is the subject and it was won by two Japanese scientists. In sentence 4, "These inventions won't be used much," the inventions are the subject and they won't be used much. In sentence 5, "Lots of interesting research is being done at the moment," the research is the subject and it is being done. In sentence 6, "Their machine has been taken," the machine is the subject and it has been taken.

However, in sentence 3, "Johan Pettersson won the Chemistry lg Nobel prize," the subject is Johan Pettersson and he is the one performing the action of winning the prize. Therefore, sentence 3 is not in the passive voice.

Moving on to the alternative choices for each rule:

1) We use the passive when we are interested mainly in the action/person who does the action.
- This rule describes the use of the passive voice when the focus is on the action being done or when it is not important to know who is performing the action.

Examples: The prizes are given to scientists. (focus on the action of giving prizes) vs Johan Pettersson won the Chemistry Ig Nobel prize. (focus on the person winning the prize)

2) We use the passive when it is/isn't obvious who does or did the action.
- This rule explains that the passive voice is used when the doer of the action is not known or when it is not important to mention the doer.

Examples: An Ig Nobel prize was won by two Japanese scientists. (doer not mentioned) vs Their machine has been taken. (doer not mentioned)

3) When we use the passive, we don't always know the person who does the action.
- This rule states that in the passive voice, it is not always necessary to know or mention the person who performs the action.

Examples: The prizes are given to scientists. (doer not mentioned) vs Johan Pettersson won the Chemistry Ig Nobel prize. (doer mentioned)

Now, let's answer the questions about the passive sentences in 1a:

1) Which tense is each passive sentence written in?
- Sentence 1: present simple passive tense ("are given")
- Sentence 2: past simple passive tense ("was won")
- Sentence 4: future simple passive tense ("won't be used")
- Sentence 5: present continuous passive tense ("is being done")
- Sentence 6: present perfect passive tense ("has been taken")

2) What changes in different tenses of the passive - the verb to be or the past participle?
- In different tenses of the passive voice, the verb "to be" changes based on the tense, while the past participle of the main verb remains the same.

Examples:
- The prizes are given (present simple passive, "are" changes)
- An Ig Nobel prize was won (past simple passive, "was" changes)
- These inventions won't be used (future simple passive, "won't be" changes)
- Lots of interesting research is being done (present continuous passive, "is being" changes)
- Their machine has been taken (present perfect passive, "has been" changes)

3) What preposition do we use to introduce the agent (the person or thing which does the action)?
- The preposition "by" is used to introduce the agent in the passive voice when we want to mention or emphasize the person or thing performing the action.

Examples:
- An Ig Nobel prize was won by two Japanese scientists. (agent: two Japanese scientists)
- Their machine has been taken by someone. (agent: someone)