declarative??? interrogative ?

While i was teaching a young student, i got lost in defining types of sentences; declaratvies, interrogatives, imperatives and exclamatories.
Here are the very questions.
1) A trip to Bahamas -> What kind of sentences is this?
I think it is incompleted sentenc, however his teacher taught him this is IMPERATIVE.
2) Who wants to go with me -> What kind of sentneces is this?
I think it is totally interrogative. But, his teacher taught him this is DECLARATIVE.
Please teach me why i can't get his teacher's teaching.
please help me~! it's very urgent.

[Tdol]

1- It's incomplete- there's no verb, so it's a sentence fragment or a monor sentence, depending on which term you prefer.
2- Declarative is a mood, which is what the teacher is referring to:
http://www.usingenglish.com/glossary/declarative.html

[dewfull]

Thanks a lot.
I always have problems using grammatical terms in English, which is not my mother tongue.
Thanks you for your answer. I really appreciate it.

[Tdol]

You're welcome.