The dreaming astronomer
There lived astronomer who was very much interested in his observations. He 7 ________ to look up at the sky at night and to observe the stars. Once, as he was walking and looking up at the stars at the same time, his leg slipped and he 8_________ into a canal. He started shouting A passer-by, who 9________ his shouts, helped him out of the canal and asked, "How did you fall into this canal?" The astronomer replied, "I was so busy 10________ my observations that I did not notice it". The passer-by asked, "How 11_________ you expect to discover things when you don't take notice of things under your nose?" The astronomer walked away with a sad face.
№7 1. uses. 2.used. 3. is using. 4. use
№8. 1. fell. 2. fall. 3.felt. 4.falled
№9. 1. is hearing 2.has heard 3.heard 4.hear
№10 1.with. 2. in. 3.of. 4. to
№11 1. is 2.does 3.did 4.do
*с объснением, почему вставили это слово, пожалуйста*​