2. Can
• I can ride a horse. ability
• We can stay with my brother when we are
in Paris. opportunity
• She cannot stay out after 10 PM.
permission
• Can you hand me the stapler? request
• Any child can grow up to be president.
possibility
3. • Anyone can become rich and famous if
they know the right people. Learning a
language can be a real challenge.
• a generalization or a supposition.
4. • It can't cost more than a dollar or two. You
can't be 45! I thought you were about 18
years old.
5. Could
• Extreme rain could cause the river to flood the
city. possibility
• Nancy could ski like a pro by the age of 11. past
ability
• You could see a movie or go out to dinner.
suggestion
• Could I use your computer to email my boss?
request
• We could go on the trip if I didn't have to work
this weekend. conditional
6. possibility
• 1. John could be the one who stole the money.
• 2. John could have been the one who stole the
money.
• 3. John could go to jail for stealing the money.
• 1. Mary couldn't be the one who stole the
money.
• 2. Mary couldn't have been the one who stole
the money.
• 3. Mary couldn't possibly go to jail for the crime.
• You can also use might, may
7. "Could not" vs. "Might not"
• Jack might not have the key. Maybe he
does not have the key.
• Jack could not have the key. It is
impossible that he has the key.
8. Must
• This must be the right address! certainty
• Students must pass an entrance
examination to study at this school.
necessity
• You must take some medicine for that
cough. strong recommendation
• Jenny, you must not play in the street!
prohibition
9. certainty
• That must be Jerry. They said he was tall
with bright red hair.
• That must have been the right restaurant.
There are no other restaurants on this
street.
• You can also use “have to”
10. prohibition
• You must not swim in that river. It's full of
crocodiles.
• You must not forget to take your malaria
medication while your are in the tropics.
• Prohibition usually refers to the near
future.
11. strong
recommendation
• (Americans prefer the form "should.")
• You must take some time off and get some rest.
• You should take some time off next week to get
some rest.
• You mustn't drink so much. It's not good for
your health.
• You shouldn't have drunk so much. That caused
the accident.
• You shouldn't drink at the party. You are going
to be the designated driver.
12. necessity
• (Americans prefer the form "have to.")
• You must have a permit to enter the national
park.
• We had to have a permit to enter the park.
• We must get a permit to enter the park next
week.
• We don't have to get a permit to enter the
national park.
• We didn't have to get a permit to enter the
national park.
• We won't have to get a permit to enter the
national park.
13. "Must not" vs. "Do not have to"
• You must not eat that. It is forbidden, it is
not allowed.
• You don't have to eat that. You can if you
want to, but it is not necessary.
14. May
• Cheryl may be at home, or perhaps at
work. possibility
• Johnny, you may leave the table when
you have finished your dinner. give
permission
• May I use your bathroom? request
permission
15. possibility
• Jack may be upset. I can't really tell if he is
annoyed or tired.
• Jack may have been upset. I couldn't really tell if
he was annoyed or tired.
• Jack may get upset if you don't tell him the truth.
• Jack may not be upset. Perhaps he is tired.
• Jack may not have been upset. Perhaps he was
tired.
• Jack may not get upset, even if you tell him the
truth
16. might
• Your purse might be in the living room.
possibility
• If I didn't have to work, I might go with
you. conditional
• You might visit the botanical gardens
during your visit. suggestion
• Might I borrow your pen? request
17. possibility
• She might be on the bus. I think her car is having
problems.
• She might have taken the bus. I'm not sure how she got
to work.
• She might take the bus to get home. I don't think Bill will
be able to give her a ride.
• She might not be on the bus. She might be walking
home.
• She might not have taken the bus. She might have
walked home.
• She might not take the bus. She might get a ride from
Bill.