Should we say in or at the class / on or in the holiday ?

Question

Should we say in or at the class / on or in the holiday ?

Answer 1

i.e.

We are going ON holiday

Zoe is in class (school class)

hope that helps.

Answer 2

She is in my class.  I am in the class.  We will be in the class.

She is going on holiday.  I am on holiday.  We will be on holiday.

Always this way.  It changes from in to on or at, depending on the noun.  There is no hard and fast rule.