This is a common phrase used in Spanish to ask about the nature or quality of classes. It can refer to:
* The content of the classes: Are they interesting, challenging, easy, etc.?
* The teaching style: Is the teacher engaging, helpful, demanding, etc.?
* The atmosphere of the classroom: Is it friendly, competitive, relaxed, etc.?
Here are some examples of how you might use this phrase:
* "Como son las clases de español?" (How are the Spanish classes?)
* "Me gustaría saber como son las clases de matemáticas." (I would like to know how the math classes are.)
* "¿Como son las clases en la nueva escuela?" (How are the classes at the new school?)