My first dog was a native yellow dog. My grandfather bought it when it got old.
My second dog was an old-looking pug. One day he knocked over the pesticide on the windowsill.
My third dog, a snow-white fox dog, got lost from my grandfather's house and never came back.
My fourth dog was born to the mother of the second dog. It is white and I call it Maomao.
Later, when I grew up and left home, I never kept a dog again.