the chemical formula for water

Teacher: What the chemical formula for water is the ?
Blonde: "HIJKLMNO"!!
Teacher: What are you talking about?
Blonde: Yesterday you said its H to O!

水的分子式

老师：水的分子式是什么？
花瓶：HIJKLMNO！！
老师：你在说什么？
花瓶：昨天你不是说H to O吗？