able，capable
这一对词都是形容词，又都含有“能够”、“能干”之意，但涵义和使用场合有所不同，大致有如下几点区别：
（一）在用作定语表示“能*”意味时，able所描述的范围较概括，able 最常用词，多用于褒义，着重指多方面的，经常性的，或潜在性的能力。有时也指高超、非凡的能力。capable所描述的范围较专注，因为前者指某人聪明能干，有多才多艺的概括涵义；后者仅指具有应付某一特指工作要求的能力。例：
She is the ablest girl I’ve ever met. 她是我见到过的最有才*姑娘。
She is an able teacher
她是个能*教师。
the ablest student in the class
班上最有才华的学生
He made a very able speech. 他作了一篇很出色的讲话。
He is an able man. 他是一个能*人。
She is a capable teacher．
她是个能胜任工作的教师。
capable 语气弱于able，指有能力、有潜力或有条件做某事，常与of连用。
She was perfectly capable of taking care of herself. 她完全有能力照顾自己。
（二）able指“能够”，是一时之现象；capable常用以指“能力”，是经常的现象。如：
I shall not be able to come to the office tomorrow．
明天我不能到办公室来（指由于某种原因而暂时不能来）。
She'd love to be able to play the piano.
她很希望能弹钢琴。
She is incapable of manual labour．
她不能从事体力劳动（指由于某种长期或经常的原因，例如患病而不能劳动）。
（三）指某人（物）能作某事时，able之后接动词不定式，capable之后接介词of。例如：
A good auditorium will assure that the sound is able to be heard from every seat.
好的礼堂能保证每个座位的听众都能听到声音。
We are able to get back to town before dark．
我们能够天黑之前赶回市区。
The larger firm was capable of providing a better range of services.
较大的公司能够提供一系列更好的服务。
Every student in the class is capable of passing the exam.
班上每个同学都有能力通过这次考试。
He was capable of killing a man with his bare hands.
他赤手空拳就能取人性命。
Are you inferring I'm not capable of doing the job?
你的言外之意是不是我不能胜任这份工作？
I believe I am capable of calculating the political consequences accurately
我觉得我能准确预料此事的政治后果。
They are not capable of doing the work．
他们没有能力做这件工作。
A run to Southampton showed the car was capable of a reasonable journey.
南安普敦之行表明这辆车还是挺能跑的。
A running track should be capable of absorbing the impact of a runner's foot landing on it.
跑道应该能够吸收奔跑者踩踏地面时产生的撞击力。
The hall is capable of holding about three hundred people.
这个大厅能容纳大约三百人。
（四）capable除表示“有能力的”意味外，还可用以表示“有可能的”涵义，able则没有这个用法。如：
One man is capable of destroying the whole world.
只要一个人就有可能摧毁全世界。
The situation is capable of improvement．
此情况有可能好转。
She has an aged parent who's capable of being very difficult.
她有一个年迈的父亲，可能会很不好相处。
The public are capable of holding a number of apparently contradictory attitudes.
公众可能会持有数种显然互相矛盾的态度。
That oil tanker is capable of being restored．
那艘油轮有可能修好。
I had no hesitation in calling the police because I realised he was capable of murder.
我意识到他可能要*人，所以就毫不犹豫地报了警。
This book is capable of being translated． 这本书可以翻译。
That law is capable of being evaded．那项法律是可以逃避的。
（五） able 一般用作正面意义，指好人好事；capable 则是中性词，既可指好事，亦可指坏事，例如在下例中，capable of anything是表示“任何坏事都做得出来”之意：
That guy is capable of anything！
那家伙什么勾当都会干得出来！
It is hard to imagine Lineker capable of anything so extreme
很难想象莱恩克尔能做出如此极端的事情。
They are capable of the most heinous acts.
他们能做出最邪恶的事情。
He’s capable of any crime.他什么坏事都能做得出来。
（六） able的反义词是unable；capable的反义词是incapable。另一点值得注意的是，able的名词是 ability，义：“能力”（the power to do）；capable的名词是capability 或 capacity，前者义：“具有从事某事的能力”；后者义：“容量”或“受容力”。需要在此指出的是，ability是可以通过练习或锻炼获得的，通常具有指具体的某种能力；而capability则是固有的能力，它与练习或锻炼无关，还指军事能力。通过例句的对比，达到融会贯通：
I do not doubt his ability to do the work．
我不怀疑他的工作能力。
She has the ability to run her father's business.
她有能力经营父亲的企业。
I have serious reservations about his ability to do the job.
我非常怀疑他有没有能力胜任这项工作。
He has blind faith in doctors' ability to find a cure.
他盲目相信医生有妙手回春的能力。
He has the ability to bring out the best in others.
他能做到扬人之长。
The ability to tolerate pain varies from person to person.
对疼痛的忍受力因人而异。
Depression lowers the human ability to cope with disease.
抑郁症会降低人体对疾病的抵抗力。
It is clear that the ability to smile is inborn.
显然，笑的能力是与生俱来的。
Overcrowding has taxed the city's ability to deal with waste
人口过多使得城市的垃圾处理能力达到了极限。
The public never had faith in his ability to handle the job
公众从来不相信他有能力胜任这一职位。
Human beings have an infinite capacity for self-deception.
人类自欺的本事是无穷的。
capacity n. 能力，才能；容纳能力；指人理解或做某事的能力，或容器、房间等的容纳能力，常后接介词 of/for。
He has a capacity for computers.他具有操作计算机的能力。
The fuel tank has a capacity of 50 litres.这个油箱能装50升油。
He has the capability to benefit from university education．
他有能力从大学教育中受益。
Animals in the zoo have lost the capability to catch/of catching food for themselves.
动物园的动物已经丧失自己捕食的能力。
Age affects the range of a person's capabilities.
年龄影响着一个人能力的大小。
She has the capability to handle the work.
她具备处理这项工作的能力。
Their military capability has been reduced because their air force has proved not to be effective
由于空军战斗力不够强大，他们的军事实力有所下降。
Britain's nuclear/military capability
英国的核力量 / 军事力量
They have the capability to destroy the enemy in days rather than weeks.
他们有能力在几天内，而不是几个星期内消灭敌人。
顺便说一下competent 强调具有能胜任某项工作的足够技能或其它所需的条件。如：
He is such a competent teacher that many schools want to hire him. 他是一位很有能力的老师，所以许多学校都争相聘请他。
We have to admit that he’s a competent man. 我们得承认他是一个很称职的人。
As he became more competent he was given more interesting work. 随着他能力的增长，他被托付以更有意义的工作。
