The present perfect tense consists of the verb have(has)+ past participle.
Basic usage of the present perfect tense
1) means that the action has been completed or just completed so far, which is often expressed by "le" or "guo" in Chinese. For example:
I have finished my work. I have finished my work.
We have established many new factors in this regard. We have set up many new factories in this area.
She has read all these books. She has read all these books.
2) The action was completed in the past, indicating "experience" or "result". Guo is a common word in Chinese. For example:
Have you seen the play A Doll's House? Have you seen the play The Puppet Family?
Yes, I have seen it twice. I have seen it twice.
I have learned to drive. I learned to drive.
This man has been living in China. This man lives in China.
[Note] Pay attention to the meaning of be in the following sentences. For example:
Where have you been? I've been to the lab. Where have you been? -I went to the lab.
Have you ever been to Hangzhou? -No, I have never been there. Have you ever been to Hangzhou? I haven't been there.
How are you doing? -I'm fine, thank you. How have you been recently? Thank you. I've been doing well recently.
The difference between the present perfect tense and the past simple tense
Both the present perfect tense and the past simple tense indicate the action completed in the past, but the present perfect tense emphasizes the relationship between this action and the present, such as the result and the influence on the present, while the past simple tense indicates that the action occurred in the past, generally not the relationship with the present. Try to compare:
I lost my pen. I lost my pen. I haven't found it yet, and now I don't have a pen. )
Yes, she lost her pen today. She lost her pen yesterday. I lost my pen yesterday. It did not say whether it was found now. )
I have been to the agricultural exhibition. I have seen this agricultural exhibition. (emphasize that I know its content)
I went to the agricultural exhibition last week. I visited this agricultural exhibition last week. It's just that I visited the exhibition last week.
3) Who opened the door? Who opened the door? (Now the door is still open)
Who opened the door? Who opened the door? (refers to the past and has nothing to do with the present. It doesn't say whether the door is closed or open now. )
Have you had lunch? Have you eaten the New Year's Eve dinner? Don't you feel hungry now? )
Yes, I do. I do. I am full now, so don't eat any more. )
When did you have it? When did you eat it? What the speaker is interested in is when the action of "eating" will happen. )
B: I was wearing it about half an hour ago. I ate it about half an hour ago.
Other uses of the present perfect tense
1) can also indicate that the action happened in the past, and has continued to the present, and may even continue. This is usually used with phrases or clauses led by since or phrases led by for (for can sometimes be omitted).
How long have you been in Beijing? I have been in Beijing for four years. How long did you stay in Beijing? I stayed in Beijing for four years.
Isaac's father has been a school teacher since 1968. Isaac's father has been a teacher since 1968.
We haven't had a holiday for a long time. We haven't had a holiday for a long time.
It has been three years since we left school. It has been three years since we graduated.
[Note] But in the following sentences, the predicate verb of the main sentence can be in the present general tense. For example:
It has been three years since I started working on a state farm. I worked on a state farm for three years. (American English uses has, and so does the following example.)
It's been a long time since I last saw you. Haven't seen you for a long time.
2) Indicate the actions to be completed in the future in the adverbial clauses of conditions and time.
I will go with you after I finish my homework, and I will go with you after I finish my homework.
We will wait here until you finish writing the letter. We will wait for you to finish writing the letter here.
After I have studied English for two years, I will know more English. After two afternoons, I may know more English.
The adverbial of time in the present perfect tense
1) The present perfect tense describes the present situation, not the present tense, so it cannot be used with adverbials indicating past time, such as yesterday, 1asr month, three years ago, l960, etc. These adverbials of time can only be used with the past tense to indicate past actions. But the present perfect tense can be used with adverbs to indicate the past time. For example:
He just arrived. He has just arrived.
We have seen this film before, we have seen this film before.
I hope it helps you. Thank you.