I want to go shopping because I have not bought any clothes in a long time.
"want" is in the present tense, which means I want to go shopping now. The time of orientation of the first verb is the present. But the speaker has to go back from the present time to the past to express what has or has not happened. "I have not bought any clothes" means that the speaker has not bought clothes since some time in the past until now.
If the time of orientation of the discourse is in the past, you can not use the present perfect tense.
wrong a. Margie graduated from high school. Then she has entered a very good college.
right b.Margie graduated from high school. Then she entered a very good college.
right c. Margie is smart. She has entered a very good college.
Sentence (a) is wrong because the first sentence begins in the past. She graduated from high school first. Then she entered college, still a past event. So the next sentence should be in the past as well, as in sentence (b). Sentence (c) is correct because the first sentence begins in the present, "is", which is a present condition. Then we have to go back into the past to explain why she is smart now. She is smart because she has entered, some time in the past, a very good college. Her entering a college in the past is related to her present condition.
Some common adverbs used with the present perfect tense are ever, never, already, yet, still, just.
a. Sally loves the movie Gladiator. She has seen it five times.
Notice that the verb "loves" in sentence (a) is in the present tense. It is a present condition. But when and how many times did she see the movie? Some time in the past, many times before now. So the verb in the second sentence must be in the present perfect, "has seen". Sentence (b) is also expressing a present situation; Mr. Johnson started grading tests some time in the past, but right now he is not finished, which is a present condition.
- Affirmative Statements: has/have + past participle
- Julie has been a dancer for three years
- The politicians have voted on the campaign finance reform.
- Negative Statements: has/have + not + past participle
- Julie has not danced in three years.
- The politicians have not voted on the campaign finance reform.
- Questions: has/have + subject + past participle
- How long has Julie been a dancer?
- Have the politicians voted on the campaign finance reform?
Present Perfect Progressive
The main difference between the present perfect and the present perfect progressive is that the progressive tense emphasizes the duration of an activity that began in the past and is continuing in the present. The event is still happening in the present time. The present perfect progressive tense occurs often with for, since, all morning, all day, all week, etc.
- Tim has been studying for a test since last week. He will do very well on it. (He started studying last week and is still studying because the test is some time in the future.)
- I have been running errands all day long. (I started running errands in the morning and I'm not done yet.)
- My sister has been making her own clothes for many years now. (She started making her own clothes a long time ago and is still making them.)
You cannot put stative verbs in the present perfect progressive tense. They can only be in the present perfect tense.
wrong: I have been knowing John for seven years.
right: I have known John for seven years.
wrong:George has been having his car since 1998.
right: George has had his car since 1998.
Some common words and expressions used with the present perfect progressive tense are recently, lately, these days, which indicate that the action started a short time ago and has continued to the present time. It implies that the action or event is fairly new or recent.
My teacher has been giving us a lot of homework lately. (He didn't use to give us a lot of homework. But a few days ago, he started to give us a lot more.)
- Kelly has been dating. We're very happy for her. (She started dating not too long ago. This is her new boyfriend.)
Affirmative statements: has/have + been + verb-ing
- Mr. Davis has been teaching for twelve years.
- We have been waiting for the bus since 5 o'clock.
- Negative Statements: has/have + not + been + verb-ing
- Mr. Davis has not been teaching since 1995.
- I have not been working since I got laid off last month.
- Questions: has/have + subject + been + verb-ing
- Has Mr. Davis been teaching for a long time?
- What have you been doing with your free time lately?
Just as the time of orientation for the present perfect tense is the present, the time of orientation for the past perfect tense is the past. The discourse begins at a certain time in the past, but when it needs to go back into the past even further, that is when the past perfect tense is used.
a. I failed the test because I hadn't studied enough for it.
b. When we saw Akiko last week, she had lost a lot of weight.
c. We arrived at the airport after the plane had already left.
In sentence (a) "failed" is in the past tense, indicating that the event took place in the past. But when did the speaker study for the test? Before the test took place. So the discourse moved further into the past, which requires the past perfect tense. In sentence (b), Akiko had lost weight before we saw her. In sentence (c), the verb in the first part of the sentence, "arrived" establishes the time of orientation as the past. But the second verb "had left" indicates that the plane left before they arrived. It took place before a past event. So were they able to get on the plane? No, they weren't.
Some subordinators that may require the past perfect tense in the independent clause are when, after, before, by the time.
wrong: By the time he had been five years old, he learned to read.
right: By the time he was five years old, he had learned to read.
right: He had learned to read by the time he was five years old.
wrong: When I had come home, my family already ate dinner.
right: When I came home, my family had already eaten dinner.
right: My family had already eaten dinner when I came home.
But look at the sentences below:
d. When we arrived at the airport, the plane left.
e. When Bruce went to Africa, he lost a lot of weight.
In sentence (d), both the verb in the dependent clause, "arrived", and the verb in the independent clause, "left", are in the simple past tense. It means they arrived at the airport first. Then the plane took off. Did they get on the plane? They probably did. In sentence (e), Bruce first went to Africa, then he lost a lot of weight.
If the past events are listed in succession, or in sequence, then the past perfect tense is not used. This is often the case when adverbial conjunctions of sequence, first, second, then, next, finally, etc., are used.
wrong: The plane had already left. Then we arrived at the airport.
right: The plane left. Then we arrived at the airport.
wrong: First, we had graduated from high school. Next, we went to college.
right: First, we graduated from high school. Next, we went to college.
Affirmative Statements: had + past participle
- By the time I graduated from college, I had already found a job.
- Negative Statements: had + not + past participle
- When Walter graduated from college, he had not found a job yet.
- Questions: had + subject + participle
- Had Walter found a job by the time he graduated from college?
- What had Mae done before she came to the U.S.?
Past Perfect Progressive
The rules for the past perfect progressive are the same as those for the present perfect progressive, except that the time of orientation is the past. The past perfect progressive is used to describe an event that was in progress at another moment in the past or that had completed just before another event in the past.
- We had been sleeping for two hours when you called us. (We went to bed two hours before you called us. We were still sleeping when you called.)
- When I saw my cousin last month, he looked really good. He had been exercising regularly. (He started exercising several months ago. He was still exercising regularly when I saw him. )
- Affirmative Statements: had + been + verb-ing
- Benjamin had been waiting for 30 minutes by the time we got to the restaurant.
- Negative Statements: had + not + been + verb-ing
- Benjamin had not been waiting long by the time we got to the restaurant.
- Questions: had + subject + been + verb-ing
- How long had Benjamin been waiting by the time we got to the restaurant?