Why "niet" is at the end of the sentence and not right after the verb - "wij zien niet het boek" ?
It is Dutch Grammar
Because that's how Dutch is. I wish I could give you a better answer, but there isn't one. The order English uses is strange in the eyes of speakers of other languages.
Is "boek" a "het" word always?
"See" means "zien". You use "zien" rather than "zie" or "ziet", because the subject is "wij".
I recall someone saying that geen is used much more than "niet", so I tried it here, but got marked wrong. I did have the sense that geen works better for plurals. Help, anybody?
'Niet' is used to negate a verb, 'geen' is used to negate a noun:
Why 'wij' and not 'we' ?