Interrogative syntax:
(1) Yes-no/polar
“Will there be tax increases?”
(2) Alternative/disjunctive
“Was that the fault of the Chancellor or are you to blame?”
(3) Wh-/interrogative word
"Who, why, when, which, what, where, or how, etc.”
“How will you pay for that?”
Non-interrogative syntax:
(4) Declarative
“There will be increases in VAT?”
(5) “Moodless”
“22%?”
(6) Indirect
“Many people have asked the question why did you go to war in Iraq?”