In this topic, you are going to learn how to make deductions about past events.
Digital Think House. (2017). (n.t). Retrieved 16/02/17 from http://bit.ly/2lYPB7h
DEDUCTION: the act or process of using logic or reason to form a conclusion or opinion about something: the act or process of deducing something.
Taken from Merriam Webster Dictionary
By the end of the topic, you will use the modals verbs must, may, might and could, to make deductions in the context of past situations. So, let’s start!
MiroAlt. (2014). Lluvia de ideas. Retrieved 16/02/17 from https://pixabay.com/es/lluvia-de-ideas-creo-que-clase-411589/
“ I am very sure…” “ Probably…” “Maybe..”
Example:
(n.a). (2010). Spencer corset 1941 before after. Retrieved 16/02/17 from
https://commons.wikimedia.org/wiki/File:Spencer_corset_1941_before_after.jpg
Martha lost almost 10 pounds in six months right before her wedding.
How did it happend?
a) She followed a very effective diet
b) She went to the gym every day.
c) She stopped drinking soda
ALL THESE ANSWERS ARE PROBABLE, BUT NOT AT THE SAME LEVEL.
Let’s see:
Here we explain what happened to Martha on three different levels.
“I am very sure Martha followed a very effective diet”
“Probably Martha went to the gym every day.” 
“Maybe she stopped drinking soda.” 
We use
to express that someone had the ABILITY or chance to do something but did not do it.
Examples:
You could have studied Medicine, but you decided to study Law. (You had a scholarship offer, but you declined it).
I did not know my father would be sleeping when I got home. I could have used his car!
As you can see in examples below the structure of modal verbs for deduction about the past is as it follows :
Activity 1
Order the sentences to make deductions about what happened at Miguel’s birthday party.
Order the sentences to make deductions about what happened at the jewellery that was robbed yesterday.
Activity 2
People discuss for so many reasons. Do you usually argue with people?
Diana and Uriel are a couple, and they live together in Mexico City. They love each other, but they argue a lot.
You will hear five conversations. Read the statements and choose the most appropriate option for each one. You can know your score at the end of the exercise.
Activity 3
We have seen so many shocking events in history. But some people have some questions about them.
Do you have questions about some of them?
Visit this website and read the article. Then you will make some deductions about what you read.
Write an opinion essay ( a text where you give your opinión about the article you just read-) following the guidelines below:
Activity 4
What did you learn about the conspiracy theories from the reading section?
Do you think these theories are possible?
Who must have wanted the death of JF Kennedy or Princess Diana?
Who might have planned these tragic events?
Think about your answers to these questions. Remember to make deductions.
Before recording yourself, study the aspects that will be evaluated, they are described in the following checklist. A rubric will be used.
Once you are ready, you will record your audio.
When we consider some present evidence and draw a conclusion about a past event, we use must have, may have and might have according to the level of probability and certainty we think.
Examples:
• British Council. (n.d.). Modals- deduction past. Retrieved from https://learnenglish.britishcouncil.org/es/quick-grammar/modals-deduction-past
• Murphy, R. (2012). English Grammar in Use. Intermediate. Cambridge: CUP. [4th ed]
• Payne, S. (2014). JFK Assassination, 9/11 attacks, Diana's Death: Why are Americans Obsessed with Conspiracy Theories? Retrieved 16/02/17 from https://www.ibtimes.co.uk/jfk-assassination-9-11-attacks-dianas-death-why-are-americans-obsessed-conspiracy-theories-1450604