Making Deductions in English: It Can’t Be That Hard!

Making Deductions in English: It Can’t Be That Hard!

by Lingoda Team

Updated November 10, 2022

Making guesses

Do you fancy yourself as a bit of a Sherlock Holmes? Maybe you enjoy having a gossip with your friends. Or, you find yourself bombarded with hard-to-solve problems and need a way to map out your thoughts in English. We use modal verbs of deduction to say how sure we are about something. Deduction is a fancy way of saying ‘making guesses based on evidence’. Sometimes we’re really sure something is true; sometimes we’re not sure; and sometimes we’re absolutely sure something isn’t true. Have a look at the situation below.

Your colleague quit her job and moved to Germany:

“She must have a taste for Bratwurst and men in Lederhosen.” (You’re sure; that’s all they eat and wear in Germany, right?) “She might be trying to finally meet Rammstein.” (You’re not sure, but she’s always had a thing for hard German rock.) “She can’t be happy drinking all that beer – she was always more of a wine person.” (You’re sure because she used to drink wine like a fish).

Your friend announces he’s becoming a professional dog walker. You can use modals of deduction to react from more supportive to less:

“Wow, that must be a really fun job! I love animals.” “I suppose that could be alright if you like working outside.” “That can’t be much fun. Shovelling poop all day long.” dog-walker-learning-english


It’s a bad habit but most of us do it: gossiping is like playing a guessing game most of the time. You have a tiny bit of information, which may or may not be true, and you spin your own stories around it. Here are a couple of scenarios you might find familiar.

A lady in her 70s has just announced her engagement to a man in his 20s:

“She must be rich.” “He may really be in love with her.” “He can’t find her interesting, all she does is drink gin and play golf.”  

Flicking through a celebrity magazine, you come across some interesting pictures. Now you might want to deduce what happened in the past:

“He must have had Botox, his forehead is like concrete.” “She might have had a boob job; they look a bit perky for a 50 year old.” “He can’t have taken care of himself very well – he’s only 47 but looks at least 60.” gossiping-women-english-learning

Mysteries and lateral thinking

When something happens we can’t immediately explain, we make deductions to say what we think happened.

If you come home to find your Christmas tree on the floor, ornaments scattered everywhere, you might say:

“Oh it must have been the dog – Rover, come here!” Meanwhile, the cat looks on slyly. Mysteries or crime stories are especially fun ways to practise modals of deduction.  motobike-english-deductions

Let’s walk through a classic lateral thinking puzzle – make guesses yourself!

A man rides up to a border in the middle of the desert with two sacks on his motorbike. The customs officer asks him what’s in the sacks. “Sand,” the man replies. The customs officer checks and sees the sacks are full of sand. He’s puzzled, but lets the man go. This continues every week for 2 years – the same man, always with two sacks of sand. In the end the customs officer can’t stand it. He begs the man to tell him: “What are you smuggling? I can’t sleep at night.” What do you think? “The man must be crazy.” “He may be selling the sand to dumb tourists.” “He might just be enjoying torturing the poor customs officer.” “There could be something else in the sand.” “The sand can’t be the real reason he’s crossing the border.” Lateral thinking is great when you have to solve a problem or a mystery by being creative, and modal verbs of deduction are there to help you through in English. (By the way, the man was smuggling motorbikes!)

So many modals

Modal verbs can be used in various different situations.  Check out our video with Zach about the modals of obligation, and our blog about the modals of obligation and  probability. There are also many lessons (currently 14!) within the Lingoda curriculum linked the the topic. Visit our website today to find out more.

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