Modal of deduction

We use must to say that...

• it’s impossible that something is true

• something is possibly true

• we are sure that something is true

We use can’t to say that...

• it’s impossible that something is true

• something is possibly true

• we are sure that something is true

We use could/may/might to say that...

• it’s impossible that something is true

• something is possibly true

• we are sure that something is true

Of course John isn't here today. He spent the whole night drinking. He ___ be at home with a serious hangover.

• may
• can't
• must
• will

Tags

CCSS.L.4.1C

CCSS.L.9-10.1B

You ___ know Peter because he went to the same school that we went to but he is a few years younger than we are.

• will
• must
• can't
• might 

Tags

CCSS.L.4.1C

CCSS.L.9-10.1B

You ___ possibly be tired. You've just woken up.

• must
• could
• can
• can't

Tags

CCSS.L.4.1C

CCSS.L.9-10.1B

They ___ be Spanish, they're speaking French.

• can
• might
• could
• can't

I'm sorry, you ___ be confusing me with someone else, that's not my name.

• can
• could
• must
• might

Tags

CCSS.L.4.1C

CCSS.L.9-10.1B

I don't believe I got 100% on the quiz.

• That must be true.

• That could be true.

• That can´t be true

I'm almost certain I know the answer.

• It must be 134!

• That's right!

• It could be 134!

• it might be 134!