I live in a very old town which is surrounded (Present Indefinite) by beautiful woods. On Sundays many people walk in the woods. Visitors are asked (Present Indefinite) to keep the woods clean. Litter baskets have been placed (Present Perfect) under the trees. Yesterday I went to the woods. What I saw there made me sad. The litter baskets were empty and the ground was covered (Past Indefinite) with pieces of paper. Among the paper and rubbish was found (Past Indefinite) a sign which said that those who leave litter in the woods will be prosecuted (Future Indefinite).