Present Perfect Continuous: Emphasis on Duration

Present Perfect Continuous emphasises duration of an action that started earlier and is still going (or has just stopped, with a visible result).

Form: have / has been + -ing.

• I have been waiting for an hour.
• She has been studying English since May.
• You're wet. Have you been running?

Simple vs continuous: result / quantity → Simple; how long / process → Continuous.

• I have written three emails. (finished)
• I have been writing emails all morning. (process)

Stative verbs usually stay Simple: I've known her for years, not I've been knowing.