What have they done?
They've just robbed a bank.
What has he done?
He's just broken the window.
What's he done?
He's just cought a fish
What have they done?
They've just had a dinner.
What's happened?
She's just fallen down.
Where has he been?
He's just been to the swimming pool.
What's happened?
He's just missed the bus.
What's happened?
She's just woken up. The alarm clock's just rung.