Describing Probability

Slide 1

• Present - Less Sure
• We use may, might and could to say that something is possible, but not certain:
• The lost treasure could/might be in a cave
• But the treasure might not even exist

Slide 2

• Present - More Sure
• We use can't or couldn't to say that something is impossible:
• Ex: It can't /couldn't be in that cave. It's too high.
• That can't be true.
• We use must to show we are sure something is true:
• Ex: There are may jewels on this necklace. It's must be very valuable.
• No one's ever found it. It must not exist.

Slide 3

• Past - Less Sure
• We use may have, might have or could have to make guesses about the past and when we are not sure that something happened in the past.
• Formula: Modal + Have + Past Participle (3 Coluna)
• This house could/might have belonged to the Royal Family
• However, it might not have belonged to an important person at all.

Slide 4

• Past - More Sure
• We use can’t have + past participle or couldn't have +Past Participle to say that we are quite sure that something did NOT happen or was NOT true in the past.
• There are bedrooms in the building, so it couldn't have been a temple.
• She can’t have passed the test. She didn’t even open the books.
• We use must have + past participle to say that we are quite sure that something was true or happened in the past.
• This house is huge so it must have belonged to the Royal Family.
• I can’t find my wallet! I must have dropped it in the taxi.