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It's Sunday morning. And it's a fine day. Xiaoyu is wearing a T-shirt and shorts. Because he is going to play baseball with his friends. His sister is writing a letter to her friend, Alice. Because she misses Alice very much. Their mum is cleaning the house. Because it's dirty. Their dad is in the supermarket. He is buying some food. Because they are going to visit Xiaoyu's grandparents this afternoon. They are going to have a big dinner in the evening.