We use MUST when we are 100% sure that it is true.Example: Croak, croak!
It must be a frog.
We use MAY, MIGHT or COULD when we think that something is possible.
Example: I don’t know the time, but it might be late.
We could try to open it. We may open it.
We use CAN’T when we think that something is impossible.
Example: You can’t be my brother. I am the only child in my family.
Do you know Sherlock Holmes? Click on the image and learn how he worked on deduction.
Do you want to practice the use of these modal verbs?