enter

to wear (shoes, pants, or other items below the waist)

slipper for indoor use, indoor shoe

classroom

to go in; to come in / 要る: to be necessary, to be required

to enter, go into, get into a place or a thing / to join a group or organization / to be contained (in), to be included (in) / to be a member of a group, set, category

school (institution dedicated to teaching and learning)

(education) instruction that takes place outside of a classroom (field trip, etc.) / (education) class that takes place in its own specialized room instead of homeroom (such as music or cooking)

expenses

sneak into, slip into