1. Conclusions: Must,
Have (got) to, May,
Might, Could, Can’t
A Visit to the
Doctor

2. Am I OK?
So, what
There are
Well, I have seems to be
several
What could We’ll need to
the problem?
possibilities.
terrible pain
the problem take some
in my
be? X-rays and
stomach.
do some
tests to find
out.

3. Meaning
We often make guesses and draw conclusions about
present situations using the information we have.
Positive 100% Certain Negative
must can’t, couldn’t
We use modals to show how
have (got) to
certain must not we are
or uncertain
may aboutmay conclusions.
our not
might, could might not
0% Certain

4. Affirmative Conclusions
When we are almost 100% certain, we use must, have
to, or have got to to state affirmative conclusions.
Mr. Jones must have
I looked at all the test
results, and I ulcer. to the
an talked
patient. I believe that…
He has to be in pain.
He’s got to be very
uncomfortable.

5. Possibilities
When we are less certain about our conclusion, we use may,
might, or could to express that something is possible.
I see something Mr. Jones could have
unusual. an ulcer.
He may have an
infection.
He might be very
sick.

6. Look at each part of the photograph one
Practice 1 at a time. Try to guess what it is.
Increase the certainty of your guesses by
using the appropriate modals.
100% Certain
This might be …
must
have (got) to
may
might, could
0% Certain
An X-ray of the heart
and lungs.

7. Negative Conclusions 1
Use can’t and couldn’t when you are almost 100% certain
that something is impossible. Use must not when you are
slightly less certain.
It can’t be an
The X-rays
infection.
look good.
The patient couldn’t
have heartburn.
It must not be
serious.

8. Negative Conclusions 2
Use may not and might not when you are
even less certain.
Your illness might not
be serious.
You may not need to
stay in the hospital.

9. Questions
Use can and could in questions.
What can the
The test results
problem be?
are not clear.
Could the patient
need surgery?

10. Look at the objects under a
microscope. Ask and answer
Practice 2 questions about possibility. Use
positive and negative modals.
Example:
1. 2.
5.
It may be a It can’t be
What could
skin.
Itfeather.
must be
it be?
cotton fibers.
3. 4.
stomach of a spider (#5) eye of an insect (#2) a feather (#3)
cotton fibers (Example) tongue of a snail (#4) skin (#1)

11. Short Answers
In short answers, use a modal alone.
Does the
Does he
He may not. patient
need a
The surgeon have a
He has to. cast?
might broken
He was in a
operate first. bone?
serious
accident.

12. Be Careful!
Use be in short answers to questions that
include be.
Could that Oh wait. It
I’m not sure.
be an image has to be.
It might be.
of my brain? I see the
brain stem.

13. Ask and answer questions
Practice 3 about the X-rays. Use
short answers.
Possible Questions Possible Answers
Could that X-ray
Could X-ray # ___ be a ___? It has to be./It’s got to be.
be a knee?___? It might be.
Can X-ray #___ be a It may/might/could be.
1. 2.
Example:
knee shoulder brain