How Are Questions Signaled by Greek Writers?

Queries in Greek are indicated by the occurrence of
interrogative pronouns and adverbs. Aristotle's τί ἐστιν
("What is it?") is a famous metaphysical
question. One can also ask τίς ἐστιν ("Who is it?) in
Greek as well (1 John 2:22). Other interrogatives are ποῖος ("What
sort?"), πόσος ("How much?"), ποῦ ("Where?") and πόθεν
("From where?"). There are more interrogatives, but I
think you get the idea.

For other NT examples, see Mt 6:31; Lk 3:10. However, it is
important to keep in mind that not all interrogative
sentences contain interrogative pronouns or adverbs
like τί, τίς or ποῦ (compare Jn 19:15). A book that
might help in this area is Brooks and Winbery's
Syntax of NT Greek. See pp. 115, 119, 125ff, 158ff.

"When no other indicator is present, whether the
sentence is a question or not must be determined by
the context" (Brooks and Winbery, p. 158).