Put the verbs in brackets into the correct tense form and

Put the verbs in brackets into the correct tense form and voice.
1)- Who ______ this park ______ (to found) by?
- It ______ (to found) by local authorities 35 years ago.
2)- How many animals _______ (to keep) in this Zoo last year?
- Last year we _______ (to keep) more than 100 animals.
3)- _______ the measures to protect this area from pollution ______ (to take) yet?
- No, they _______ (to discuss) at the moment.
4) - _______ you _______ (to write) the letters already?
- The letters _______ (to write) at the moment.
5)- _______ they _______ (to solve) this problem yet?
- No, it _______ (to solve) tomorrow.