Can to talk about a present ability or possibility and with future meaning

CAN, COULD, BE ABLE TO
ABILITY AND POSSIBILITY

We use CAN to talk about a PRESENT ABILITY or POSSIBILITY and with FUTURE MEANING. Can is always followed by a bare infinitive (without to)

Eg. I can ride a horse (ability)
She can’t come this evening (possibility)
He can see you tomorrow (future meaning)

We use COULD to talk about a PAST ABILITY, POSSIBILITY and with CONDITIONAL. Could is also followed by a bare infinitive (without to)

Eg. She could speak Chinese when she was twelve because she lived in China (ability)

He arrived in time and could catch the 7.00 a.m. train (possibility)
I could do it if I had the means (conditional)

With VERBS OF SENSES we use CAN or COULD, not BE ABLE TO

Eg. I can’t see very well
As soon as I entered the house I could smell what she was cooking

We use BE ABLE TO to talk about ABILITY and POSSIBILITY in ALL TENSES

EXCEPT THE CONTINUOUS TENSES. BE ABLE TO can also be used in the
present and in the past but it is more formal than CAN and COULD.

We also use BE ABLE TO in THE GERUND and THE INFINITIVE WITH TO

FOR A SPECIFIC SITUATION in which we MANAGED TO DO SOMETHING,
use BE ABLE TO, not COULD


After modals we use BE ABLE TO

Eg. I’d like to be able to play the guitar (infinitive)

She loves being able to stay with us on holidays (gerund)
She’s been able to paint for years (present perfect)
I won’t be able to come to your party (future)
He didn’t have much time but he was able to hand in his essay on Monday (specific situation when we managed to do something)
She must be able to run very fast to become a police officer (be able to after a modal verb)
EXERCICE
Complete the following sentences with the following modals

Can	Could	Be able to
Can’t	Couldn’t	Not be able to

1). .................................. you translate in Spanish?

2). I have................................... (not) start the engine. I think it has broken down.
3). His daughter ..................................... speak three languages when she was only seven.
4). Sorry, I will ....................................... (not) see you tomorrow. I’ll be very busy.
5). I’d love ........................................ go with you to the museum, but I’m afraid it will be impossible
6) Five years ago, I .................................... (not) speak English at all
7). We had a flat tire on the way to London, but finally we ......................................... find a breakdown van and reached our destination.
8). We should ............................................ answer the questions without looking up in a dictionary.
9). I................................... write with my right hand. I’m left-handed.
10). They’ve never ...................................... understand a word of Russian
11). ..................................... you help me with my homework?
12). He remembers ............................................ open the door after several attempts.
13). She used to ............................................. drive on the left we she lived in England
14). He hates ........................................ (not) tell her the truth.
15). We ..................................meet after work if you didn’t have to go to the dentist’s
16). I ...................................... come tomorrow, I have to study for my exams.
17). I’ve been so busy, I ............................................. (not) answer my emails.
18). I will ........................................ get married when I am 20.
19). I ......................................... fly a helicopter
20). The printer wasn’t working this morning but luckily my colleague ....................................... repair it in the end.

KEY

1). CAN you translate in Spanish?
2). I HAVEN’T BEEN ABLE TO start the engine. I think it has broken down.
3). His daughter COULD speak three languages when she was only seven.
4). Sorry, I WON’T BE ABLE TO see you tomorrow. I’ll be very busy.
5). I’d love TO BE ABLE TO go with you to the museum, but I’m afraid it will be impossible
6) Five years ago, I COULDN’T speak English at all
7). We had a flat tire on the way to London, but finally we WERE ABLE TO find a breakdown van and reached our destination.
8). We should BE ABLE TO answer the questions without looking up in a dictionary.
9). I CAN’T write with my right hand. I’m left-handed.
10). They’ve never BEEN ABLE TO understand a word of Russian
11). CAN you help me with my homework?
12). He remembers HAVING BEEN ABLE TO open the door after several attempts.
13). She used to BE ABLE TO drive on the left we she lived in England
14). He hates NOT BEING ABLE TO/NOT HAVING BEEN ABLE tell her the truth.
15). We COULD meet after work if you didn’t have to go to the dentist’s
16). I CAN’T/WON’T BE ABLE TO come tomorrow, I have to study for my exams.
17). I’ve been so busy, I HAVEN’T BEEN ABLE TO answer my emails.
18). I will BE ABLE TO get married when I am 20.
19). I CAN fly a helicopter
20). The printer wasn’t working this morning but luckily my colleague WAS ABLE TO repair it in the end.