1. He finished the project for five days.
2. He has finished the project for five days.
3. He read the book for five days.
4. He has read the book for five days.
[Are the four sentences all grammatical?}
5. He read the book in five days.
6. He finished reading the book in five days.
[What is the difference between #4 and #5? Does #5 mean #6?]
"For" is the wrong preposition. It makes no sense. Five and six are correct.
https://www.merriam-webster.com/dictionary/for
The four sentences are grammatically correct.
The difference between #4 and #5 is the use of the word "in."
#4 "He has read the book for five days" means that he started reading the book five days ago and is still currently reading it.
#5 "He read the book in five days" means that he completed reading the entire book within a time frame of five days.
#6 "He finished reading the book in five days" has the same meaning as #5.
1. The sentence "He finished the project for five days." is not grammatically correct. To fix it, you could say: "He finished the project in five days." This implies that it took him five days to complete the project.
2. The sentence "He has finished the project for five days." is also not grammatically correct. To make it grammatically correct, you could say: "He has been finished with the project for five days." This means that he finished the project five days ago and has been done with it since then.
3. The sentence "He read the book for five days." is grammatically correct. It means that he spent five days engaged in the act of reading the book.
4. The sentence "He has read the book for five days." is grammatically correct. It implies that he started reading the book five days ago and is still currently reading it.
5. The sentence "He read the book in five days." is grammatically correct. It indicates that it took him five days to complete reading the entire book.
6. The sentence "He finished reading the book in five days." is also grammatically correct. It means that he completed reading the book within a time period of five days.
The difference between #4 and #5 is that #4 implies an ongoing action of reading the book for five days, while #5 indicates the time it took to complete reading the entire book. #5 does not necessarily mean #6, as #6 specifies the action of finishing reading the book and does not indicate whether he started or completed the reading within five days.