How to Write a Past Story from a Given Sentence - B1 English Writing — Exercise 1

The message arrived while I was waiting for the last bus home. I almost ignored it, 1 — choose —becausealthoughso my phone showed an unknown number. It said, “Your backpack is still at the library.” I looked down and realised that I 2 — choose —had takenwas takingwould take somebody else's bag by mistake. Feeling embarrassed, I 3 — choose —gothad gotwas getting off the bus and ran back towards the town centre. When I reached the library, a security guard 4 — choose —was standingstoodhad stood by the locked entrance. He explained that a student 5 — choose —had foundfoundwould find my backpack under a desk after the building had closed. 6 — choose —RelievedAmusedDisappointed, I showed him the message and described the bag I was carrying. He phoned the student, who 7 — choose —was waitinghad waitedwould wait for me at a café nearby. A few minutes later, I met Leo. He was relieved because his laptop was in the bag I 8 — choose —had takenwas takingwould take. I apologised and promised that I 9 — choose —wouldhadwas check the name tag more carefully in future. We exchanged our backpacks and laughed about the mistake. If the library guard had not helped us, we 10 — choose —wouldhadwere both have spent a very anxious night.