英语能力表达课程 - TOEIC®备考
在英语中，表达自己能做什么、不能做什么，或者过去能够做什么非常重要。本章节将教你如何使用 can、could 以及 be able to，还有其他用于表达能力或取得成绩的实用表达方式。
1. "Can"用于表达能力（现在时）
情态动词 can 是现在时表达能力最常见的方式。它的用法非常简单，对于第三人称单数（he/she/it）不需要变化。
A. 如何使用 “can”？
| 形式 | 结构 | 示例 |
|---|---|---|
| 肯定句 | 主语 + can + 动词原形 | I can speak three languages. (我能说三种语言。) She can drive a car. (她会/能开车。) |
| 否定句 | 主语 + cannot (can't) + 动词原形 | He can't swim. (他不会游泳 / 他没有能力游泳。) They can’t come tonight. (他们今晚不能来：无法脱身或其他原因) |
| 疑问句 | Can + 主语 + 动词原形 | Can you help me? (你能帮我吗？) Can they fix the computer? (他们能修好电脑吗？) |
B. 什么时候用 “can”？
- 用于表达一般能力（身体、智力等）
- I can lift 50 kilos.
(身体能力) - She can solve complicated math problems.
(智力能力)
- I can lift 50 kilos.
- 用于表达许可/允许（扩展自“可能性”的概念）
- You can use my phone if you want.
(“许可”概念) - 本课程主要聚焦能力表达，如果你想了解更多许可表达，请阅读本课程关于许可。
- You can use my phone if you want.
- 用于表达可能发生的事实（非正式语境）
- It can get really hot here in summer.
(这里夏天可能很热，这是自然现象)
- It can get really hot here in summer.
C. 什么时候用 “can't”？
- 用于表达一般无法做到（身体、智力等）
- I can't lift 50 kilos.
(身体无法) - She can't solve complicated math problems.
(智力无法)
- I can't lift 50 kilos.
- 用于表达逻辑或情境上的不可能
- You can't be serious!
(在逻辑上不可能) - He can't be at home; I just saw him at the store.
(根据事实逻辑推断不可能)
- You can't be serious!
- 用于表达禁止（非正式场合）
- You can't park here.
(你不能在这里停车：非正式的禁止) - They can't enter the building without a badge.
(没有工牌不能进楼)
- You can't park here.
- 用于表达挫折或极限
- I can't understand this math problem.
(我无法理解这道数学题) - She can't stop laughing.
(她忍不住笑：个人或情境上的极限)
- I can't understand this math problem.
2. “Could”用于表达过去的能力（或假设性）
情态动词 could 主要用于表达过去的能力或者假设性场景下的能力。
A. 如何使用 “could”？
| 形式 | 结构 | 示例 |
|---|---|---|
| 肯定句 | 主语 + could + 动词原形 | I could run very fast when I was a kid. (我小时候能跑得很快) She could read when she was only four. (她四岁时就会读书) |
| 否定句 | 主语 + could not (couldn't) + 动词原形 | We couldn't finish the project yesterday. (我们昨天没能完成项目) He couldn't find his keys. (他没找到钥匙) |
| 疑问句 | Could + 主语 + 动词原形 | Could you understand the instructions? (你能理解这些说明吗？) Could he play the piano as a child? (他小时候会弹钢琴吗？) |
B. 什么时候用 “could”？
- 过去的能力（一般情况）
- When I was young, I could climb trees easily.
(童年时习惯性能力)
- When I was young, I could climb trees easily.
- 假设/条件语境下的能力
- I could help you if I had more time.
(如果我有更多时间，我可以帮助你) - They could win the match if they trained harder.
(如果他们更努力训练，他们可能赢得比赛)
- I could help you if I had more time.
- 礼貌请求/建议（比“can”更柔和）
- Could you lend me a pen?
(你能借我一支笔吗？) - We could go to the cinema tonight.
(我们今晚可以去看电影)
- Could you lend me a pen?
C. 什么时候用 “couldn't”？
- 过去无法做到（身体、智力等）
- I couldn't lift 50 kilos when I was younger.
(过去身体无法) - She couldn't solve complicated math problems as a child.
(小时无法解决复杂数学题)
- I couldn't lift 50 kilos when I was younger.
- 过去的逻辑或情境上的不可能
- He couldn't have been at the meeting; he was out of town.
(根据事实推断过去不可能) - They couldn't have finished the project so quickly.
(根据过去事实逻辑推断不可能)
- He couldn't have been at the meeting; he was out of town.
- 表达过去的禁止或拒绝
- We couldn't enter the building without a badge.
(我们以前没有工牌不能进楼) - She couldn't go to the party because her parents said no.
(因为父母不同意，她没能去参加聚会)
- We couldn't enter the building without a badge.
- 表达未能成功或缺乏成就
- I couldn't find my keys yesterday.
(昨天我没找着我的钥匙) - They couldn't fix the computer on time.
(他们没能按时修好电脑)
- I couldn't find my keys yesterday.
- 表达假设下的无法做到
- I couldn't live without my phone.
(假设下我无法离开手机) - He couldn't do that, even if he tried.
(即使他努力了也做不到)
- I couldn't live without my phone.
3. “Be able to”用于各个时态表达能力
与 can 和 could 不同，be able to 可以用于所有时态。因此它通常被称为“半情态动词”，而不是纯情态动词。
A. 如何使用 “be able to”？
基本结构：主语 + be（对应时态变形）+ able to + 动词原形 + 可选补语
-
现在时
形式 结构 肯定句 I am able to swim across the lake.
(我能横渡湖泊)否定句 I am not able to understand this concept.
(我无法理解这个概念)疑问句 Are you able to help me with this exercise?
(你能帮我做这个练习吗？) -
过去时
形式 结构 肯定句 We were able to contact the manager yesterday.
(我们昨天联系上了经理)否定句 We were not able to contact the manager yesterday.
(我们昨天没能联系上经理)疑问句 Were you able to contact the manager yesterday?
(你昨天联系上经理了吗？) -
将来时
形式 结构 肯定句 She will be able to travel next month.
(她下个月将能去旅行)否定句 She will not be able to travel next month.
(她下个月不能去旅行)疑问句 Will she be able to travel next month?
(她下个月能去旅行吗？) -
现在完成时
形式 结构 肯定句 He has been able to improve his English a lot this year.
(他今年英语进步很大)否定句 He has not been able to improve his English this year.
(他今年英语没进步)疑问句 Has he been able to improve his English this year?
(他今年英语有进步吗？)
B. 什么时候用 “be able to”？
- 当“can”或“could”在某些语法时态下不可用时。不能说 “I have can...” 或 “I will can...”，此时需要用“be able to”。
- I have been able to save some money.
(而不是 “I have can save...”)
- I have been able to save some money.
- 强调（某一时刻）取得的成功
- We were able to solve the problem at the last minute.
(我们成功在最后一刻解决了问题)
- We were able to solve the problem at the last minute.
- 表达对未来行动的确定性
- I will be able to drive next year.
(我明年就能开车了)
- I will be able to drive next year.
4. 其他表达能力的方式
虽然 can、could 和 be able to 最常用，但还有其他表达能力或成就的方式：
- Manage to + 动词原形：强调克服困难后完成了某事。
- I managed to fix the bike despite having no tools.
(我在没有工具的情况下修好了自行车)
- I managed to fix the bike despite having no tools.
- Succeed in + V-ing：类似于“manage to”，但更正式，突出努力后的成功。
- She succeeded in persuading her boss.
(她成功说服了老板) - He succeeded in finishing all his tasks before the deadline.
(他成功在截止前完成了所有任务)
- She succeeded in persuading her boss.
- Know how to + 动词原形：强调技能或技巧。
- He knows how to program in Python.
(他会用Python编程)
- He knows how to program in Python.
- Be capable of + V-ing / 名词：更正式地表达能力。
- They are capable of solving complex problems.
(他们有能力解决复杂问题)
- They are capable of solving complex problems.
5. 能力表达方式的比较与细微差别
介绍完所有情态动词及半情态动词（及其表达方式）后，下面分析它们的差异与使用细节。
A. “Can” vs. “Could”
- Can（现在时）：当前、直接的能力或简单场合的许可。
- I can swim.
(我会游泳 / 我能游泳)
- I can swim.
- Could（过去/假设性）：过去（习惯性）能力或条件下的能力。
- I could swim when I was five.
(童年时的一般能力) - I could help you if I had some free time.
(假设性能力)
- I could swim when I was five.
B. “Can”/“Could” vs. “Be able to”
比较1： “Be able to” 可用于所有时态（现在、过去、将来、完成时等），而 “can / could” 则不能。
- He has been able to find a better job.
(现在完成时)
比较2： “Could”通常表达过去一般能力，而“Was able to”则强调某次具体成功。
| 示例 | 细微差别 |
|---|---|
| When I was a kid, I could climb trees. | 一般能力（经常发生） |
| Yesterday, I was able to climb that tall tree. | 昨天完成一次特殊挑战 |
结论
以下为英语能力表达的总览表：
| 表达方式 | 主要细微差别 | 示例 |
|---|---|---|
| can | 现在时能力，非正式许可 | I can play piano. |
| could | 过去一般能力或假设/条件能力 | I could run fast as a child. |
| be able to (am/is/are...) | 可用于所有时态+强调某次成功 | I was able to contact him yesterday. |
| manage to + 动词原形 | 克服障碍后成功完成某事 | She managed to fix her car without professional help. |
| succeed in + V-ing | 成就（通常较正式） | They succeeded in saving enough money to travel. |
| know how to + 动词原形 | 技能或智力能力 | He knows how to bake perfect bread. |
| Be capable of + V-ing / 名词 | 正式能力，理论上的潜力 | This machine is capable of processing large amounts of data. |
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