The document discusses when to use passive voice and how to transform sentences from active to passive voice. It notes that passive voice is used when the actor is unknown, irrelevant, or to be vague about responsibility. It also notes passive voice emphasizes the object of the action and is commonly used in scientific writing. The document then provides examples of how to transform active sentences to passive by making the direct object the subject and using forms of "to be" plus the past participle of the verb.

2. When do I use passive voice?
• The actor is unknown:
The paintings were made in the twentieth century. [We don't know who
made them.]
• The actor is irrelevant:
An experimental solar power plant will be built in the Australian desert. [We
are not interested in who is building it.]
• You want to be vague about who is responsible:
Mistakes were made. [Common in bureaucratic writing!]

3. • You are talking about a general truth:
Rules are made to be broken. [By whomever, whenever.]
• You want to emphasize the person or thing acted on. For example, it may be
your main topic:
Insulin was first discovered in 1921 by researchers at the University of
Toronto. It is still the only treatment available for diabetes.
• You are writing in a scientific genre that traditionally relies on passive voice.
Passive voice is often preferred in lab reports and scientific research
papers, most notably in the Materials and Methods section:
The sodium hydroxide was dissolved in water. This solution was then
titrated with hydrochloric acid.

4. How do we transform an active sentence into a passive
sentence?
1. The direct object of the active sentence becomes the subject (Pacient) of the
passive sentence.
2. We have to change the verb. We put the verb “to be” in the tense of the
active voice sentence, followed by the original verb in the past participle
form.
3. The active subject becomes the agent, always introduced by the preposition
“by”.

5. EXAMPLES:
Present Simple: take/s ---is/are taken
Past Simple: took---was taken
Present Perfect: have/has taken---has been taken
Past Perfect Simple: had taken---had been taken
Future with will: will take---will be taken
Going to future: going to be taken
Modal verb: must/can/should be

6. Ahora algunas expresiones que cambian al pasar a la voz
pasiva.
DIRECT SPEECH
REPORTED SPEECH
now
Then, at that moment
Today
That day
Tonight
That night
Last night
The previous night, the night before
Tomorrow
The next day, the following day
Yesterday
The precious day, the day before
This week
That week
Next week
The following week, the week after
Last year
The previous year, the year before
here
there

7. EXAMPLES OF THE PASSIVE VOICE:
 He writes a book--------A book is written
 He is writing a book----A book is being written
 He wrote a book------A book was written
 He was writing a book----A book was being written
 He will write a book----A book will be written