u/Traditional-Arm-5710

Declarative that looks like a question

So I have started to read "Catcher in rye" to expand my vocab and I noticed peculiar sentences, that looks like question, but it's meaning is declarative. For example:

"Boy, could he get on your nerves sometimes." = He is really irksome. Why not just swap could and he?

What are these sentences called?

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u/Traditional-Arm-5710 — 12 hours ago