Put the verbs in brackets into the correct tense form and

Put the verbs in brackets into the correct tense form and voice.
1)- _____ they_____ still ( to work) in the garden?
_ No, the work ________ ( to finish) already.
2)-______ the tickets ________ ( to book) yet?
-Yes they ___________ ( to deliver ) in an hour.
3) - When ________ this zoo _______ ( to found ) ?
- It _______ ( to found ) fifty years ago.