1. They will come back home in a few
days.
2. They will come back home in a
several days.
3. They will come back home in a
couple of days.
4. They will come back home in some
days.
(What is the difference between them?)
Oh, my! When to use or not use articles is something ingrained in native English speakers, but is almost impossible to understand if you're not. I have a Korean friend who has lived in the U.S. for about 10 years, since she was 10 years old. She's now in college and writes and speaks nearly perfect English, but still occasionally misses an article.
That said --
#s 1 and 3 are correct. #s 2 and 4 are wrong.
The difference between the phrases 1-4 lies in the use of different quantifiers to convey the same general meaning.
1. "They will come back home in a few days."
The phrase "a few" implies a small, unspecified number of days. It suggests that they will return home relatively soon, but it does not specify how many days exactly.
2. "They will come back home in several days."
The term "several" typically means more than a few, indicating a greater number of days. It suggests that they will return home after a longer period of time than "a few," but it remains somewhat vague in terms of the exact number of days.
3. "They will come back home in a couple of days."
The phrase "a couple of" usually indicates two days. It implies a relatively short duration until their return, specifically suggesting that they will be back home within two days.
4. "They will come back home in some days."
The term "some" is less precise than "a few" or "several" and does not provide a specific number. It generally indicates an unspecified amount of time but implies that it will be longer than "a few" or "a couple of" days.
In summary, "a few" implies a small number of days, "several" suggests more than a few, "a couple of" signifies two days, and "some" indicates an unspecified number of days.