Grammar: Complete the text with the Past Simple or Past Continuous forms of the verbs in brackets.

It was a warm day. The sun was shining (shine) and the birds were singing (sing) in the sky. Suddenly, the explorers heard (hear) a strange noise in the forest. They didn't know (not know) what it was. So, what were they doing (they/ do)? They ran (run) back to. **Перевод:** Был теплый день. Солнце сияло, и птицы пели в небе. Внезапно исследователи услышали странный шум в лесу. Они не знали, что это было. Итак, что они делали? Они побежали обратно.