Present perfect or past simple? -what are you doing this weekend? -i dont know. i/not/decide/yet. -i cant find my adressbook. have you seen it? -it/on the table/last night. -are you hungry? -i/just/eat. -paula and sue are here? -are they? what time/they/arrive?

- What are you doing this weekend? 
- I don't know. I haven't decided yet.

- I cant find my address book. Have you seen it?
- It was on the table last night.

- Are you hungry?
- I have just eaten.

- Paula and Sue are here.
- Are they? What time did they arrive?