Past Modals of speculation

Unit 9

PAST MODALS

OF SPECULATION

PAST MODAL STUCTURE

mustmay might could can´t

past participle verb

have

The volcano+might+HAVE+made+that loud sound.the birds must have gone somewhere warm. he can't have passED through that door. it is too small.

DEGREE OF CERTAINTY

100%

100%

50%

Use these modals to make deductions or speculate about the past.

Why do you think Katie is looking so relaxed?

She must have gone on vacation.She may have won the lottery. She might have had a beach house. She could have lived by the beach. She can't have been working.

PRACTICE TIME!!

Lisa's car is not at the front way. She may have left already.

The light in Scot's room was on. He could have been playing computer games.

His bike is not there! It must have been stolen.

It's too early to have finished the exam. He can't have finished.

We use past modals to speculate on past events.

May have / Might have = something possibly happened (but we aren’t sure if it did)

“They may have left early because of the holiday traffic.” (= Maybe they left early…) “They might have taken the train.” (= Maybe they took the train.) The negative form is “might not have“: “He might not have received the message.” (= Maybe he didn’t receive the message.)

We use past modals to speculate on past events.

Could have = something was possible in theory

“He could have become a doctor. (= He had the ability to become a doctor, but he didn’t.) The negative form is “couldn’t have“: “He couldn’t have seen you – it was too dark.”

We use past modals to speculate on past events.

Can’t have = something was not logically possible

“She can’t have passed the exam. “she didn’t study at all!”

We use past modals to speculate on past events.

Must have = we are sure about something

“You must have known that we had a test today, because the teacher sent us all a message.”

MORE PRACTICE

1. He __ committed the crime, as he had both the motive and the opportunity. a. can't have b. could have

2. Lucy __ attended the concert, but we aren't sure. a. can't have b. may have

3. You __ finished that book already! You only started reading it an hour ago. a. can't have b. might have

4. I think they __ got lost - surely they'd be here by now! a. can have b. must have

5. She __ been a lawyer but she decided to study accountancy instead. a. could have b. may have

ANSWERS:

1. He __ committed the crime, as he had both the motive and the opportunity. a. can't have b. could have

2. Lucy __ attended the concert, but we aren't sure. a. can't have b. may have

3. You __ finished that book already! You only started reading it an hour ago. a. can't have b. might have

4. I think they __ got lost - surely they'd be here by now! a. can have b. must have

5. She __ been a lawyer but she decided to study accountancy instead. a. could have b. may have

THANKS!

Grace Mogollón