Complete the text with the Past Simple Past Continuos form of the verbs in brackets.
I (a).............(sit) in my English lesson this morning when I (b)...............(see) something strange through the window. A hot-air-balloon (c)...............(fly) straight towards the school!

Suddenly, while I (d)..............(watch) the balloon? it (e)..............(crash) into our school building! I was so surprised! Fortunately, everyone was OK.