这道英语完形填空怎么写呢?
Dogs have been man's good friends for t________of years.Many stories told how brave dogs helped people in t_____.With the help of dogs,many people l______in snow found their way home.
Dogs have also helped in many scientific researches.The first spacetraveller was a dog n___________Laika.It was sent up in a manmade earth satelite in 1957 bY R_______scientists.
Dogs have become film stars,too.A dog called Lassie was the star in quite a few American f____________.
Dogs can h_____and s________better than man,but they can't see so well.A dog may l___________for about 12 or 13 years.A thirteen-year-old child isn't grown up yet,b___________ a thirteen-year-old dog is a very old dog indeed.