Billie is watching the suspicious neighbor. (for two hours) ➡️ Billie_________________________________________
Billie has been watching the suspicious neighbor for two hours.
She tracks down the stolen diamond. (already) ➡️ She _________________________________________.
She has already tracked down the stolen diamond.
The gadget-master is fixing her super-collar. (since 3 o'clock) ➡️ The gadget-master _________________________________________.
The gadget-master has been fixing her super-collar since 3 o'clock.