Mary is a little girl. She is only four. She is not at school. She can't read or write. But her sister Joan is a schoolgirl. She is ten years old. She can read and write.

    One day, Joan sees her little sister in the room. She is at the table. There is a pencil on her hand. She is writing.

    "What are you writing, Mary?" she asks.

    "I'm writing a letter to my friend Rose."

    "Buy how can you? You can't write," says her sister.

    "Well," says Mary, "it doesn't matter. Rose can't read"

    It is a beautiful sunny d. There isn't a cloud in the sky. Greg wto have lunch at once. Bwe decide(决定） to have a swim first. After swimming, we have a picnic lunch uthe trees. Then we lie in the sun for a while. In the a  it begins to get cloudy. At four o'clock, we have to go back because it starts to rain.

— In its house.

—       can swim.