When I was very young, I wanted to become a veterinarian   one day, because I loved animals very much, especially dogs. However, there was no room in my adult life for a dog. Then, last year, I could not stand the fact that I developed cancer  . I wanted to keep a dog, but I knew my illness made it impossible for me to keep one. In early September, to my surprise, my doctor told me that I could keep a pet as my friend, because my immune system   was strong to keep a pet. The same day I went to an animal market with my friends. When I saw a 9-week-old dog with big brown eyes, nice ears and white _ all over the body, I took it home.I'm happy these days since Oscar came into my life. My new favorite pastime is to watch him sleep, eat and run. And I have been spending more time caring about him, taking long walks with him in the park. Now I still have the physical examination once a week at the hospital. But my illness has taken a turn for the better with the company of a dog. My immune system is getting stronger, my doctor tells me. Thanks to Oscar, my life has changed a lot. From the passage, we can infer   that  _  .
the dog is hard to take care of the writer is thankful to her pet dog the writer's illness gets worse than before now the writer doesn't need any physical examination