你知道十二生肖吗？“子鼠丑牛，寅虎卯兔，辰龙巳蛇，午马未羊，申猴酉鸡，戌狗亥猪．”在这十二种动物中，都属于哺乳动物的选项是（ ）
据报道，我国已在南海某海域试采可燃冰获得成功。可燃冰分布于深海沉积物或陆域的永久冻土中，主要是由甲烷（CH4）与水在高压低温条件下形成的类冰状结晶物质，可燃烧，所以被称为“可燃冰”。
No. 1 Middle School
Don't run in the hallways
Don't bring food into the classroom.
Don't listen to music in class.
You have to wear a uniform.
No. 2 Middle School
Don't bring food into the classroom
Don't wear a hat in class.
Don't go into the classroom without the teacher.
No. 3 Middle School
Don't listen to music in the classroom.
Don't run in the hallways.
You have to wear sports shoes for gym class.
完成反射的结构叫（ ）
