1. PAST
MODALS
By: JhoanM. Tagaban
RickaMae Tolentino

3. Have+ past participle (‘have been', 'have done’) is called perfect infinitive.
When we use modal verbs to talk about the present they are followed by
an infinitive without ”to” .
When we use modal verbs to talk about the past they are followed by a
perfect infinitive.
Must+ perfect infinitive
we use must+ perfect infinitive when we feel sure about something in the
past.
Examples:
 You must have been delighted when you heard you’d won the lottery.
 The thieves must have come in through the window. Look it’s still open.
 Oh no! Where’s my car? Someone must have stolen it!

4. might/may/could/+perfect infinitive
We use might, may or could with the perfect infinitive to say that we think something
was possible but we aren’t sure.
Examples:
 The thieves might have escaped by car but we can’t be sure.
 He should be hour by now. He may have been delayed by a traffic jam or something.
 I can’t find my purse. I could have left in the supermarket but I just don’t know.
can’t + perfect infinitive
we use can’t + perfect infinitive when we feel sure something didn’t happen in the past.
Examples:
 I thought I saw John in town this morning but it can’t have been him- he’s in Greece this
week.
 I can’t have left in the supermarket- I had it on the bus on the way home.
 You can’t have read the instructions properly. They’re perfectly clear.

6.  Should Have
Use should have to say that a different action was
recommended in the past.
If you arrive late to English class, you can say:
“I should have left my house earlier.”
If you regret an argument, you can say:“I shouldn’t
have yelled at you yesterday. I’m sorry.”
You can also use should have / shouldn’t have to tell
other people that a different action in the past would
have been better. If your son fails a test, you can
say:
“You should have studied. You shouldn’t have played
video games all weekend.”

7.  Could Have
Use could have to talk about possibilities if
something had been different in the past.
For example, someone who didn’t go to college
can say:
“If I had gone to college, I could have gotten a
better job.”
When talking about a gymnast who didn’t win a
competition, you can say:
“She could have won the gold medal if she hadn’t
fallen three times.”

8.  Could have is often used with “if + had + past
participle” (If I had gone / if she hadn’t fallen) – these
“if” phrases express the imaginary past situation.
However, in some cases you can use could have
without the “if” phrase. Imagine you’re driving with a
person who makes a dangerous maneuver on the
road. You can say:
“Are you crazy? We could have gotten into an accident.”

9. Would Have
Use would have to imagine a result (if something had
been different in the past):
If you arrive late at the airport and miss your flight, you
can say:
“If we had arrived earlier, we would have caught our
flight.”
If you forget your umbrella, and it starts to rain, and you
get wet, you can say:
“If I had brought my umbrella, I wouldn’t have gotten wet
in the rain.”

10. Would have expresses more certainty about the result
than could have:
“If I had worked harder, I could have gotten a
promotion.”
(maybe I’d get a promotion… but maybe not)
On a test where you need 70% to pass:
“I got a 68 on the test. If I had gotten two more points, I
would have passed.”
(with the two points, passing the test is CERTAIN)

11. EXERCISES
Direction: write if it is must have, might have, should have, can’t have.
1. John ____ gone on holiday. I saw him this morning downtown.
2. Nobody answered the phone at the clinic. It ____ closed early.
3. I ____ revised more for my exams. I think I’ll fail.
4. Sarah looks really pleased with herself. She ____ passed her driving test this morning.
5. I didn’t know you were going to Phil’s party yesterday. You ___ told me!
6. I can’t believe Jim hasn't arrived yet. He ___ caught the wrong train.
7. I can’t believe Jim hasn't arrived yet. He ___ caught the correct train.
8. His number was buy all night. He ___ been on the phone continuously for hours.
9. It ___ been Mickey I saw at the party. He didn’t recognize me at all.

12. 1. Bill hasn’t arrived for the meeting yet, he ____(get) stuck in traffic. There’s no other possibility.
2. Sally’s car is still parked outside her house, she ___ (leave) for work yet because she always goes by car.
3. His phone is out of battery, he ___ (forget) to charge it. I’m certain of it.
4. I'm not sure where my keys have disappeared to, but I suppose I ____ (leave) them on my desk. It’s certainly
a possibility.
5. I'm not surprised you failed the job interview, you ____ (study) more!
6. You__(tell) her that her hair looked bad, she’s going to be upset with all day.
7. There are puddles of water on the pavement, it ____ (rain). It’s the only explanation
8. You behaved terribly last night, you ___ (drink) so much!
9. Its midnight already! We ____ (spend)the last three hours talking!
10. Its hard to say for certain, but the classical music performance last night ____ (be) the best I've ever heard.

13. 11. There’s a mosquito in here, it _____ (come)in through the window. No
doubt about it.
12. The government ___ (do) something about the financial situation a long
time ago.
13. I can’t believe that you won the football match, your team is terrible. You
___ (have) a lot of luck.
14. This soup is so thick and tastes so nice! They ___ (put) a lot of cream in
it.
15. I know it’s too late to say it now, but I ____ (waste) so much money on
silly things last night.

14. THANK YOU
FOR
LISTENING