The past tense is to express the past time. How about the present perfect tense? When we compare the two verb tenses, we often explain it this way: The past tense tells us what happened in the past; the present perfect tense tells us that something happened in the past, but continues until now. This is not 100% correct.
Here is a sentence:
I have bought my house for 10 years.
When you ask your students if the sentence is right or wrong, a lot of students will tell you it’s right. Actually it’s wrong. Some students may tell you it’s wrong, but they don’t know why it’s wrong.
The problem is that there are two kinds of verbs. One is the verb of one-time action, the other is the verb whose action can continue. That is why we can say “I have lived in Pasadena for 10 years,” but we cannot say “I have bought my house for 10 years.” The reason is that “live” is a verb that can continue, but “buy” is a one-time action verb. When you “buy” something, you pay for it and it’s done. The action cannot continue “for 10 years.” It doesn’t make sense. To make it correct, we have to choose another verb. If you say “I have had my house for 10 years,” there will be no problem. For the same reason, we cannot say “My grandfather has died for 10 years,” but you can say “My grandfather has been dead for 10 years.”
Having said that, I don’t mean that one-time action verbs cannot be used in the perfect tense — they can. The problem is that one-time action verbs cannot be used in the perfect tense with the time phrase. Without a time phrase, any verbs can be used in the perfect tense.
I have bought my house. (correct)
I have bought my house for 10 years. (incorrect)
My grandfather has died. (correct)
My grandfather has died for 10 years. (incorrect)
He has left for New York. (correct)
He has left for New York for a week. (incorrect)
In the correct sentences above, we cannot say the action happened in the past and continue until now because one-time action cannot continue. Actually there are two uses of the perfect tense: a)Something happened in the past and continue until now; b) something happened in the past but still have an effect on the present. It is the second use of the present tense that is used in the above correct sentences. “I have bought my house” doesn’t mean “buy” continues until now; what it means is that it has an effect on the present – I don’t need to buy a house now and I have a house to live in.
- Ron Lee