1. He read this book in a day.
2. He read this book within a day.
3. He read this book at the end of a day.
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'In' means 'within' or 'at the end of' according to a dictionary.
Q1: Does #1 mean #2?
Q2: When he read the book for 1 hour and he finished reading the book, can we say as in #1?
Q3:When he read the book for 24 hours and he finished reading the book, can we say as in #1?
Q4: Is #3 correct?
#3 is correct, but means something different than #s 1 and 2. 1 and 2 mean the same thing. #3 means that he read AFTER the normal daily activities were completed, i.e. after school or work, after the children were tucked in for the night, or whatever were activities separate from reading the book.
Q2 & 3, yes to both. A day is 24 hours. Any span within that 24 hours is "within" or "in" a day.
Thank you for your help.
Then, what is the difference betwen #4 and #5? Can we use #4, when it took one day for him to read the bok?
4. He read this book in five days.
5. He read this book within five days.
Well, yes, they do mean the same thing. "Within" means it took no longer than five days, or one day in 1 & 2. "In one day" might mean it took the whole day. Both are a little vague about exactly how long it took to read a book. They set a parameter. Maybe it only took three hours, maybe all 24 hours, but he started the book and finished it in the span of one day or five or whatever.
Q1: No, #1 does not mean #2. In #1, it states that he finished reading the book in a single day, whereas in #2, it implies that he finished reading the book at some point within a day, but it does not specify if it was completed in one sitting or spread out over multiple sittings.
Q2: No, we cannot say #1 if he finished reading the book in just 1 hour. Since #1 states that he read the book in a day, it implies that it took him a significant amount of time, closer to a full day, to finish reading it.
Q3: Yes, you can say #1 if he reads the book for 24 hours and finishes it. Since #1 states that he read the book in a day, it indicates that he took the entire day to read it, regardless of the actual duration.
Q4: No, #3 is not correct. "At the end of a day" suggests that he finished reading the book at the conclusion of the day, possibly indicating that he started reading it earlier and completed it later, near the end of the day. It does not convey the idea of completing the book within a single day.