Interrogative

a type of sentence structure used to seek information.

Compare:
 * Declarative
 * Imperative
 * Exclamative

Types of interrogative sentences

 * Yes-no questions
 * Wh- questions
 * Alternative questions

Crystal, David. Rediscover Grammar, page 49.

Bruntt, Karen and Bryanne, Ulla. Handbook for Grammar Detectives, page 113.