"What did you say? I do not understand."
nuqjatlh is a special word that stands alone as its own sentence, an exclamation. It is not simply a short form of the sentence nuq jatlh What did he/she say? You could not, for instance, say nuqjatlh HoD What did the captain say?
One of the (automatically generated?) multiple choice options starts with the one word sentence "Je." What does "je" mean?
When following a verb, je is an adverbial that means also: HoD vIleghpu' je I also saw the captain.
When following a string of nouns, je is a conjunction meaning and: HoD la' Sogh je the captain, the commander, and the lieutenant.
Well, let's see... Klingon is a fictice idiom (excuse me from my English, I am a Spanish learning), coming from Star Trek so... we all are frikies of Star Trek and all things relationated to this? (It isn't and offense, it is a conclusion)
That is not necessarily true. Many Klingon speakers are more intrigued by the language, itself, than by the TV shows. But you are correct that at least the majority of us are fans of the shows. (By the way, "idiom" is a false cognate and means "modismo".)
Eso no es necesariamente cierto. Muchos hablantes de klingon están más intrigados por el idioma en sí mismo que por los programas de televisión. Pero tienes razón en que al menos la mayoría de nosotros somos fanáticos de los programas. (Tenga en cuenta que "idiom" es un falso cognado y significa "modismo").