Yesterday I watched / was watching a funny sitcom when my sister (1) asked / was asking me to help with her homework. I (2) laughed / was laughing so much that I (3) didn’t hear / wasn’t hearing her. She (4) switched / was switching off the TV. I (5) helped / was helping her with her homework very quickly, but when I (6) switched / was switching on the TV, the sitcom (7) finished / was finishing, so I only saw a few minutes of the rest of the episode.