下列因果关系正确的是（　　）

阅读下列短文,从每小题所给的A、B、C、D四个选项中选出一个最佳选项。

Dear Bill

    Thank you for your letter（信件). You tell me something about your family. Now I'll talk about my family.

    I have a happy family. We love each other. My grandparents are doctors. They work in Canada now. My parents are both teachers. They teach English at Luoyang International School. My sister and I are in Luoyang with them.

    I'm 13 years old. I'm a student in Grade Seven. I like my teacher and my friends in China . They often help me. I want to be a Chinese doctor when I grow up . Now I can speak Chinese. My sister, Jane, is only three years old. She is very cute . She has brown hair and blue eyes. We all love her.China is very beautiful. Welcome to China.

Yours

Frank