CAN / BE ABLE TO
1. ABILITY
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He can speak two foreign languages
fluently.
He is able to speak
languages fluently.
two
foreign
My son doesn’t attend school yet, but he
can / is able to read and write already.
1. ABILITY (negative sentences)

we use “can’t” and “am/is/are not able to.
He can run very long distances, but he can’t
run very fast.
 He is able to run very long distances, but he
isn’t able to run very fast.

I can speak English, but I can’t speak French.
 I am able to speak English, but I am not able
to speak French.

2. POSSIBILITY
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I will finish my homework in an hour, so I can
help you then.
I am very busy now, so I can’t help you.
Overexposure to the sun’s rays can lead to
skin cancer.
Drinks in restaurants can be very expensive.
3. PERMISSION
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You can leave your purchases here until
you finish your shopping.
Because tomorrow is holiday, you can
stay up late tonight.
Those who have finished answering the
questions can leave the classroom.
PAST FORM OF
“CAN” AND “BE ABLE TO”
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can
be able to
could
was/were able to
I could run very fast when I was a child.
 I was able to run very fast when I was a
child.
 Some students in my previous class could
/were able to speak English almost fluently,
but they weren’t so good at grammar.

PAST FORM OF
“CAN” AND “BE ABLE TO”
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COULD” is used in ability and permission
meaning in the past.
Mozart could play the piano when he was
only four. (ability)
 My grandfather was very strong. He could
lift enormous boxes on his own. (ability)
 It was raining heavily. We could go out only
when it had stopped raining. (permission)

PAST FORM OF
“CAN” AND “BE ABLE TO”
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“WAS/WERE ABLE TO” is also used in
ability and permission meaning in the
past. However, we only use “WAS/WERE
ABLE TO” in the meaning of “manage to
do sth” in the past.
PAST FORM OF
“CAN” AND “BE ABLE TO”
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He was a good swimmer when he was a
child.
He could/was able to swim faster than all
the other children. (ability)
I had a good voice when I was younger.
I could /was able to sing very well,
especially folk song. (ability)
PAST FORM OF
“CAN” AND “BE ABLE TO”
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When their maths teacher didn’t come, the students
were able to / were allowed to leave school earlier.
(permission)
One specific event !!!


The maths exam was very difficult yesterday, but I
was able to get a high grade, anyway. (managed to get
a high grade)
Last month, there was a huge fire in our street.
Luckily, the fire brigade came just in time to
estinguish it, so everyone was able to escape unhurt.
(managed to escape unhurt)
PAST FORM OF
“CAN” AND “BE ABLE TO”
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When I was a child, I could / was able
to run very fast. I could/ was able to
beat anyone who raced with me. (ability)
Once, I raced with a school friend of
mine, She was also a fast runner. It was
a hard race for me, but I was able to
beat her in the end. (one specific)
PAST FORM OF
“CAN” AND “BE ABLE TO”
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In negative sentences, we can use both
COULD and WAS/WERE ABLE TO in three
meanings ( ability, permission and one specific
event). COULD is used more frequently.
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I couldn’t / wasn’t able to use a computer just
three months ago, but now I can.
The students didn’t want to have a test that day,
but they couldn’t / weren’t able to persuade the
teacher to cancel it.
EXERCISE
Use COULD to express “ability and permission” and WAS/WERE
ABLE TO to express “to overcome a difficult situation”
1.
He ___ swim very long distances when he was a teenager,
but after years of heavy smoking, he no longer can.
2.
We had been warned that our flight might be delayed this
morning, but the pilot ___ take off despite heavy fog.
3.
Because she ___sing better than anyone, she was asked to
do a solo at the graduation ball.
4.
Some terrorists telephoned the police to warn that they
had planted a bomb in the local shopping centre. Luckily,
the police ___ evacuate the area before it exploded.
5.
We stayed at a beautiful seaside town for our summer
holiday, and on a clear day from our hotel room, we ___
see a lot of fishing –boats on the horizon.
EXERCISE
Use COULD to express “ability and permission” and WAS/WERE
ABLE TO to express “to overcome a difficult situation”
6.
Although they had locked themselves out of their
apartment, they ___ get in through window.
7.
My old flat was behind the football stadium, and on
match days, we ___ hear the cheers of the crowd.
8.
We used to live in the mountains, so in winter, we
___ go skiing, whenever we liked.
9.
I’ m glad we ___ persuade the teacher to put
tomorrow’s exam off till next Monday. Now, we will
have plenty of time to revise.