Never shall I forget the first English lesson giving by Miss Liu. One Monday morning, when she entered into the classroom, we found that she was young and beautiful lady. Then she introduced her and said we shouldn’t call her Teacher Liu but Miss Liu. Late, she let us go to the blackboard and said something about ourselves in English in turn. When it was my turn, I felt too shy that I didn’t dare to say anything before the class. She went up to me and said kind, “Don’t be afraid. I believe you could do it well.” At last, I went to the blackboard. She praised me for that I had done.

诊断地方性砷中毒的皮肤三联症是什么？