Other & Another: the Difference in English Grammar
Let's review the grammar rules for another, other, and the other:
|another + singular nonspecific countable noun|
The nouns ("day" and "piece") in both sentences are countable and singular (e.g. not with an 's') nouns.
The nouns in both sentences are also not specific. This means that the speaker doesn't care which day or piece of cake he gets; he just wants a different one. He wants another one, but he hasn't said (or it isn't clear or important) which one.
Hint: If you understand English articles ("a/an/the"), then think of "another" as "an + other." You can use "another" before a noun whenever you can use "a(n)" before a noun. The rules are the same. Another = an other!
|other + plural or uncountable nonspecific noun|
The nouns in both sentences are not specific, just like with "another". The speaker doesn't specify which other people have problems, or what other information the book has. The rules are the same as "another" except that "other" is used before plural or uncountable nouns.
Hint: If we think about articles (a/an/the) again, then remember that we use "other" before a noun that would NOT need an article.
|the other + specific noun (singular, plural, countable or uncountable)|
The nouns ("brother" & "days") in both sentences are specific.
Re: Example #1: What brother lives in Japan? The other brother. The speaker said he has two brothers. He told you where the first brother lives, so the other brother must be his second brother. This is a specific brother (not general). You know what brother he is talking about.
Re: Example #2: What days of the week does he work on? Tuesday, Wednesday, and Friday. The speaker said he goes to school on Monday and Thursday. You know that the other days of the week are Tuesday, Wednesday, and Friday. So the speaker says "the other" because it is clear what other days of the week he works on. Specifically, they are Tuesday, Wednesday and Friday.
Hint: Thinking about articles again, the rules for "the other" are the same as the rules for "the" + noun.
Do you think you understand?
Let's see! Take the test:
Three of my friends live in Boston. One is a doctor, one is a dentist, and doesn't have a job. The friend without a job's name is Craig. Craig needs a job. He also has problem: he needs a new girlfriend. His last girlfriend left him because she met man. man was rich and handsome. I told Craig not to worry about it; there are many girls in the world.
Three of my friends live in Boston. One is a doctor, one is a dentist, and the other doesn't have a job. The friend without a job's name is Craig. Craig needs a job. He also has another problem: he needs a new girlfriend. His last girlfriend left him because she met another man. The other man was rich and handsome. I told Craig not to worry about it; there are many other girls in the world.
I hope this was helpful. As we have seen, you need to understand how to use English articles (a/an/the) to use "another/the other/other" correctly. Articles are not easy. Keep studying, practicing, and don't give up!
– Matthew Barton of Englishcurrent.com