The night shift1
Leo worked all night and has not slept. He is yawning.
Express a strong positive deduction.
Practice Lab · Unit 5 Grammar
Read the Clues
Look closely. Read the evidence.
Choose must, might or can’t.
How it works
Choose. Compare. Listen.
Read the clues and the requested meaning. Choose one answer, then compare all three explanations. Tap a picture to enlarge it.
Quick guide · must / might / can’t
must
I am almost sure it is true.
Strong positive deduction.
might
It is possible. I am not sure.
Other explanations are possible.
can’t
I am almost sure it is not true.
Strong negative deduction.
Use subject + modal + base verb: He must be tired. Here, must is a deduction, not an obligation; can’t is a deduction, not a rule or lack of ability.
Grammar workshop
What do the clues suggest?
0 / 10 answered
At the bus stop2
Sara is looking at her watch at a bus stop. You do not know her plans. Perhaps she is meeting a friend, or perhaps she is waiting for a bus.
Express a possibility, without being sure.
She ___ be waiting for a friend.
A locked library3
It is 9 p.m. The library closes at 6 p.m. today. The entrance is locked, the lights are off, and no special event is scheduled.
Express a strong negative deduction.
The library ___ be open to visitors now.
The result is in4
Mia was afraid she had failed her presentation. She has just learned that she passed. Now she smiles and her shoulders relax.
Express a strong positive deduction.
She ___ be relieved.
Before the presentation5
Ana is holding her notes tightly before speaking. You have not asked how she feels. She could be nervous, or she could simply be concentrating.
Express a possibility, without being sure.
She ___ be nervous.
A call from London6
You are in a classroom in Medellín. Your friend Emma is speaking to you on a live video call from London right now.
Express a strong negative deduction.
Emma ___ be in your classroom now.
At the museum7
The visitors lean forward, ask many questions and ask the guide to continue. They have stayed much longer than planned.
Express a strong positive deduction.
They ___ be interested in the exhibition.
During the talk8
Ben rests his cheek on his hand during a talk. You do not know whether he is bored, tired or thinking carefully.
Express a possibility, without being sure.
He ___ be bored.
The empty backpack9
Nora has emptied her backpack and checked every pocket twice. Nothing is left inside, but her keys are still missing.
Express a strong negative deduction.
The keys ___ be in the backpack.
A wet arrival10
Luis has just come in from outside. His jacket is wet, water is dripping from his umbrella, and you hear heavy rain on the roof.
Express a strong positive deduction.
It ___ be raining outside.
Practice only · Your first choices and corrections stay on this page. Reloading starts a new round.