Ответ:

1. She / make / breakfast

She's just made breakfast.

2. He / be on holiday

He's just been on holiday.

3. They / arrive

They've just arrived.

4. She / wash her hair

She's just washed her hair.

5. He / buy a ring

He's just bought a ring.

6. A Would you like a cake? B No, thanks. We / have lunch

No, thanks. We've just had lunch.