I need help understanding the usage of the word "another".
As I understand, this word is basically "an + other", which implies it should be used only with singular countable nouns, just as the indefinite article does.
However, I've seen sentences like, "He stayed there for another two weeks." Here, "another" is paired with the word "weeks", which is plural. Why is it so? Is it correct? Where would it be appropriate to use structures like this?
Thank you in advance!

Question

Answer

Another “two weeks”, the two weeks is counted as one unit of time.
Two weeks is a noun phrase.  The word “another” is a modifier for the noun phrase which means an extension of that duration of time.

Answer

"another two weeks" is a contraction of a longer phrase, which could be written more fully as "another set of two weeks" (a single set, of two weeks) or "another duration of two weeks" (a single duration of time, spanning two weeks). an even shorter way to say it, still singular, would be "another fortnight"

Answer

I think that "another" should be understood as "an additional."  When stated alone, the object of the sentence is implied:
1. "The hamburger was delicious.  I think I'll have another [one]."
2. I don't like the music of this composer.  I think I'd like to find another [composer]."

Answer

Here's an English translation of the explanation to help others understand the usage of "another," maintaining the original academic rigor and teaching intent:

---

### Explaining the Usage of "Another"

**Core Concept:**  
"Another" fundamentally means "an + other," implying it should modify **singular countable nouns** (e.g., *another book*, *another idea*).

**The Exception:**  
However, in structures like **"another + number + plural time/money unit"** (e.g., *another two weeks*, *another ten dollars*), "another" modifies an **implied singular quantity** (a block of time/amount), not the plural noun directly.

> Example:  
> * "He stayed for **another two weeks**."  
>   = He stayed for **an additional period** of two weeks.  
>   *(Here, "another" describes the singular concept of "a period.")*

---

### Key Rules:  
1. **Only Applies to Time/Money Quantities**:  
   ✅ Correct:  
   - *another three* **days**  
   - *another fifty* **dollars**  
   - *another ten* **minutes**  
   ❌ Incorrect (for ordinary plural nouns):  
   - *another two books* → Use "**two more books**" instead.

2. **Interchangeable with "number + more + noun"**:  
   - *another two weeks* = *two more weeks*  
   - *another five minutes* = *five more minutes*

3. **Contrast with Standard Singular Usage**:  
   | Type                | Example                   | Meaning                          |  
   |---------------------|---------------------------|----------------------------------|  
   | **Standard Singular** | *Give me **another apple***. | "A different/additional apple"   |  
   | **Quantified Expression** | *Wait **another ten minutes***. | "An additional ten-minute period" |

---

### Why Is This Structure Valid?  
- It’s an **established grammatical exception** in English for **measured quantities** (time/money).  
- "Another" implicitly targets the **singular unit of measurement** (e.g., "a block," "a sum").

---