Sure, here's a simple and expanded story about a family suitable for a 3rd-grade English class, including mentions of a mother, father, and grandmother:
Hello! My name is Lucy. I want to tell you about my family.
I have a small but wonderful family. My mom's name is Sarah. She is very kind and loves to cook delicious meals for us. Every morning, she makes breakfast for me and my dad. She works as a teacher at the local school. In the evening, she helps me with my homework and reads me bedtime stories.
My dad's name is John. He is very strong and funny. He works as a firefighter and helps people when they are in trouble. On weekends, he takes me to the park, and we play games together. He also loves to fix things around the house. I like spending time with my dad because he always makes me laugh.
I also have a lovely grandmother. Her name is Mary, but I call her Grandma. She lives with us in our house. Grandma is very good at knitting and makes warm sweaters for me. She tells me stories about when she was young. I love listening to her stories because they are always so interesting.
We all live in a cozy house with a beautiful garden. In the garden, we grow flowers and vegetables. My mom, dad, and I take care of the plants together. Sometimes, Grandma helps us too.
On Sundays, we have a special family day. We all sit together and have a big lunch. After that, we play board games or watch a movie. It's always so much fun to spend time with my family.
I love my family very much. They make me happy, and we always support each other. I am lucky to have such a wonderful mom, dad, and grandma!
This story includes simple vocabulary and sentence structures appropriate for a 3rd-grade English class, making it easy for young learners to understand and relate to.