Using past modals for speculation and deduction

In this post, I am describing activities where students practice using past modal verbs for speculation and deduction. I have been using them with upper-intermediate, advanced, FCE, and CAE students who often struggle with the concept of using modal verbs for something other than expressing ability or obligation.

Deduction: Crime Scene Investigation

Variant A

This activity is usually lots of fun and enables you to engage the whole group into the creation process. Here is what you need:

  • a setting (a living room, a classroom, an office etc. confined spaces usually work best)
  • a character (who sadly gets murdered in the first scene)
  • a set of clues (written words of pictures) that might be either completely random or somehow connected.

The aim of the game is to recreate the events leading to the main character’s death. Analysing clues that gradually appear during the investigation, students invent what must / might / can’t have happened at the crime scene before they arrived.

Here is a Google presentation I have been using with my students. After each clue appears, they have to produce a conclusion.

Clue #1: You look around the office, terrified. Suddenly, you notice a cigarette butt on the floor!

What is your conclusion? 

Anna might have been a smoker.  / The killer might have been a smoker. / The killer must have smoked after killing Anna.

Deducing who the killer was is not really the objective here but the students often get very engaged and invent very convincing storylines.

Download the presentation here.

Variant B

If you like improvising and work with like-minded students, you might make them responsible for the story:

without informing them where the game is going (don’t mention the murder yet) ask your students to come up with:

  • a place
  • a person
  • 10 random objects

Then, explain that the person has been found dead in the place and  10 random objects have been spotted at the crime scene. Ask your students to deduce what each object had to do with the crime using past modals. You might work together or divide your students into pairs/groups. Make sure to provide some relevant examples of the target language.






  1. Thanks a lot! I’ve just come by this great website! Terrific work! Hope to use it in my classes:)

    • Great news! I’d love to find out how these ideas worked out in practice for you 🙂

  2. Just writing to say that your posts are truly amazing! What a great job’s done! Millions of thanks!

    • That’s great to hear, thanks a lot for taking the time to comment!

  3. Hi there???? I used these lessons & exercises for my own students. They’re great????????

    • Hi Sarah, go ahead. This is a free edu resource for EFL/ESL teachers to use in their lesson. I hope your students like it!

  4. I’m gonna use the activity tomorrow in my class! It’s so creative and undoubtedly engaging. Thanks tons for sharing the brilliant ideas!

  5. Pingback: Teaching articles

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