Tra từ able - Từ điển Oxford Advanced Learner 8th

able [able abler ablest] BrE [ˈeɪbl] NAmE [ˈeɪbl] adjective
1. ~ to do sth (used as a modal verb)to have the skill, intelligence, opportunity, etc. needed to do sth
• You must be able to speak French for this job.
• A viral illness left her barely able to walk.
•I didn't feel able to disagree with him.
•Will you be able to come?
Opp: ↑unable
2. (ablerBrE [ˈeɪblə(r)] ; NAmE [ˈeɪblər] , ablestBrE [ˈeɪblɪst] ; NAmE [ˈeɪblɪst] )intelligent; good at sth
•the ablest student in the class
•We aim to help the less able in society to lead an independent life.
see also ↑ably

Word Origin:
late Middle English (also in the sense ‘easy to use, suitable’): from Old French hable, from Latin habilis ‘handy’, from habere ‘to hold’.

Word Family:
able adjective (≠ unable)
ably adverb
ability noun (≠ inability)
disabled adjective
disability noun

Grammar Point:
can / could / be able to / manage
Can is used to say that somebody knows how to do something: ▪ Can you play the piano? It is also used with verbs of seeing, noticing, etc: ▪ I can hear someone calling, and with passive infinitives: ▪ The DVD can be rented from your local store.
Can or be able to are used to say that something is possible or that somebody has the opportunity to do something: ▪ Can you/are you able to come on Saturday?
You use be able to to form the future and perfect tenses and the infinitive: ▪ You’ll be able to get a taxi outside the station. ◇ ▪ I haven’t been able to get much work done today. ◇ ▪ She’d love to be able to play the piano.
Could is used to talk about what someone was generally able to do in the past: ▪ Our daughter could walk when she was nine months old.
You use was/were able to or manage (but not could) when you are saying that something was possible on a particular occasion in the past: ▪ I was able to/managed to find some useful books in the library. ◇ I could find some useful books in the library. In negative sentences, could not can also be used: ▪ We weren’t able to/didn’t manage to/couldn’t get there in time. Could is also used with this meaning with verbs of seeing, noticing, understanding, etc: ▪ I could see there was something wrong.
Could have is used when you are saying that it was possible for somebody to do something in the past but they did not try: ▪ I could have won the game but decided to let her win.

Example Bank:
•Humans are uniquely able to use true language.
•I was just able to make out a dark figure in the distance.
•Once you've had some sleep you'll feel better able to cope.
•She is not physically able to take care of herself.
•She seems very able.
•less able students
•He was a very able man in business matters.
•I didn't feel able to disagree with him.
•She's the ablest student in the class.
•Unfortunately they weren't able to come.