3.4 Degrees of Certainty about the Present and Future

1. Section A

2. We can use simple modals and phrasal modals to
show how certain we are that something is true or is
likely to happen.
We often provide evidence or a reason for what we are
saying.
Notice that some modals show different degrees of
certainty in positive and negative sentences.

3. We use will/won’t, be going to/be not going to,
must/must not, or can’t/couldn’t/wouldn’t to express
stronger certainty in positive and negative sentences.
home at 6:00. Her schedule never changes.She‘ll be
home at 6:00. She told me so.She‘s going to be

4. She home early. She has too much work to do.won’t get
home early.She‘s not going to come

5. She’s not here, so she at work.must be
She at her desk – I called and she didn’t answer.must not be
She home already. I saw her at work five minutes ago.can’t be
She home already. I just saw her.couldn’t be

6. We use should/shouldn’t to express expectation in
positive and negative sentences. For example:
She at work by now. It usually takes her 30 minutes.should be
She home yet. She usually works until 7:00.shouldn’t be

7. We use may/may not, might/might not, or could
to express weaker certainty in positive and negative
sentences. For example:
She there already. She left before we did.may be
They tomorrow. I have to call to find out.might visit
I don’t know him. He a new student, I guess.could be

8. We don’t usually contract must not, may not, and
might not.
She didn’t get paid. She enough money to go out.may not have
They tomorrow after all.might not visit