Complete the sentences by using the Past Simple or the Past Perfect Continuous from of the verbs in brackets .
1. When Leonardo da Vinci built his helicopter he ______(work ) on his desing for many years . He ______(draw ) birds in flight to learn about aerodynamics .
2. We _____(fly) for twenty minutes when the pilot _______(announce) we had to go back because of bad weather .
3. The teacher _____(ask ) for my project on inventions for weeks when I finally _____(give) it to her last Monday .
4. I found out why my pen friends _____(not get ) my letters . I ____(send ) them to the wrong address !
5. Our favourite band ____(play) for only ten minutes when there ____(be) a power cut and the concert had to be cancelled . We were upset because we _____(die) to see them for years .