结束篇表示过去的能力如下文
Welcome to Daily Tips on Learning English. Todays 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, theres no difference in meaning. So, I couldnt lift the piano and I wasnt able to lift the piano mean the same thing. However, in affirmative sentences about past ability, could usually means 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 fixed two days ago. When I saw you today, you told me that the mechanic 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.
Lets 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 Im not able to. I was able to means I have the ability at one particular time in the past.
This has been todays daily tip on learning English. Tune in tomorrow for another tip.
以上是结束篇表示过去的能力