The document discusses the uses of can/can't and could/couldn't to describe present and past ability and permission. Can and can't are used to describe present ability and permission, while could and couldn't are used for past ability and permission. Must and mustn't express obligations and prohibitions in the present.

1. GRAMMAR 1:
can / can’t
could / couldn’t

2. Can: present ability
+ Johanna can do gymnastics at 94 years old.
- I can’t climb a tree.
? Can you run 5 km?

3. Can: present permission
+ You can read a book in class.
- You can’t eat in class.
? Can you speak in class?

4. Could: past ability
+ Elizabeth could swim when she as 14
months old.
- I couldn’t walk when I was a baby.
? Could you speak English 10 years ago?

5. Could: past permission
+ John and Su could play on the floor when
they were 3.
- Mart couldn’t stay up late when she was a
child.
? Could you go to parties with 3 years old?

6. SUMMARY
PRESENT ABILITY PRESENT PERMISSION
CAN CAN
PAST ABILITY PAST PERMISSION
COULD COULD

7. Can? Can’t? Must? Mustn’t?
You must raise your hand.

8. Can? Can’t? Must? Mustn’t?
You can ask questions in class.

9. Can? Can’t? Must? Mustn’t?
You must listen in class.

10. Can? Can’t? Must? Mustn’t?
You mustn’t fight in class.
You can’t fight in class.

11. Can? Can’t? Must? Mustn’t?
You must do your homework.

12. Can? Can’t? Must? Mustn’t?
You can’t run in class.
You mustn’t run in class.

13. Can? Can’t? Must? Mustn’t?
You can’t write on the wall.
You mustn’t write on the wall.

14. Can? Can’t? Must? Mustn’t?
You can read a book.