几 in declarative and interrogative sentence 几 has two meanings: &quot;several&quot; and &quot;how many?&quot; But I have no clear understanding of separation one from another. E.g.:

后面有几个人笑起来了. - declarative
你家有几口人? - interrogative

I know that the first sentence is declarative and the second one is interrogative but I don't know why. There is no difference in 几 usage here so why is the first sentence declarative?

A few people laughed behind [us].
And not interrogative: How many people laughed behind [us]?

&quot;几个人&quot; could be as well &quot;a few people&quot; and &quot;how many people?&quot;, how to distinguish which one is used? (An example of interrogative sentence with &quot;几个人&quot; would be useful)
P.S.: please do not give explanation like &quot;后面有几个人笑起来了.&quot; is declarative because &quot;后面有多少人笑起来了?&quot; is interrogative. I also can say that in the case &quot;你家有几口人&quot; is declarative (&quot;There are some people in your family&quot;) because there is no &quot;多少人&quot;.

Another example, you are speaking to a person and he says:

上海有几个火车站(。/？)

Only context can help you to understand whether it is a question or a declaration, right?

(on the street)
请问, 上海有几个火车站(？) - defenetely interrogative

And:

- 到火车站要10分钟, 不要着急。
- 上海有几个火车站(。)我去上海南站, 到那儿要半个小时。 - declarative
I think all the sentences with 几 above can turn into interrogative sentences. For example:


  后面有几个人笑起来了? 
  
  你家有几口人?
  
  上海有几个火车站?


In the mainland mandarin, we usually put 好 in front of 几 in the declarative sentence to indicate that there are more than one. For example:


  后面有(好)几个人笑起来了。// 好 can be omitted without changing the meaning.
  
  你家有好几口人。// 好 can not be omitted
  
  上海有好几个火车站。// 好 can not be omitted


With 好，you can differentiate if it's a declarative or interrogative sentence.  In some sentences (like the first one above), 好 is omissible. You'd better not omit 好 in the sentence 2 and 3, otherwise they would sound like interrogative sentences.