美语听力与发音技巧 listen 33

美语听力与发音技巧 第33期（表示过去的能力）

Welcome to Daily Tips on Learning¹ English. Today’s tip is on expressing ability in the past.
There are two ways of expressing ability in English. One, “can” or “could”. Two, “be able to”. In negative sentences, there’s no difference in meaning. So, “I couldn’t lift the piano” and “I wasn’t able to lift the piano” mean the same thing. However, in affirmative sentences about past ability, “could” usually means² “used be able to”. The use of “could” usually indicates that the ability existed in the past, but does not exist now.
For example, “When I was young, I could run fast” means that I can not run fast now. On the other hand, if the speaker is talking about an ability to do something at one particular time in the past, “was/were able to” can be used in affirmative sentences, but “could” cannot.
For example, your car broke down. It stopped working. So you took it to get fixed³ two days ago. When I saw you today, you told me that the mechanic⁴ fixed your car. If you said, “The mechanic could fix my car yesterday”, that sentence is not correct. You must say, “The mechanic was able to fix my car yesterday” or “The mechanic managed to fix my car yesterday.”
Let’s look at another example. I have been looking for a CD I like for a long time. I could not find it. I was not able to find it for a long time. But yesterday I was able to find it. Yesterday I managed to find it. But you cannot say, “Yesterday I could find it.”
Remember “I could not” and “I was not able to” are the same, but “I could” and “I was able to” are not the same. “I could” means I used to be able to, but now I’m not able to. “I was able to” means I have the ability at one particular time in the past.
This has been today’s daily tip on learning English. Tune⁵ in tomorrow for another tip.

1 learning   

n.学问，学识，学习；动词learn的现在分词

参考例句：

• When you are learning to ride a bicycle,you often fall off.初学骑自行车时，常会从车上掉下来。
• Learning languages isn't just a matter of remembering words.学习语言不仅仅是记些单词的事。

2 means   

n.方法，手段，折中点，物质财富

参考例句：

• That man used artful means to find out secrets.那人使用狡猾的手段获取机密。
• We must get it done by some means or other.我们总得想办法把它干完。

3 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

4 mechanic   

n.技工，机(械)工，机修工

参考例句：

• The mechanic made the necessary adjustments to the engine.机械师对发动机作了必要的调整。
• He is a mechanic who buys and sells cars on the side.他是一个兼营买卖汽车的技工。

5 tune   

n.调子；和谐，协调；v.调音，调节，调整

参考例句：

• He'd written a tune,and played it to us on the piano.他写了一段曲子，并在钢琴上弹给我们听。
• The boy beat out a tune on a tin can.那男孩在易拉罐上敲出一首曲子。