Explain how an interlocking schedule at a puerto rico school works , why are interlocking schedules use ?

An interlocking schedule is where a group of students go to school from one specific time and when they leave, others arrive.  I lived in Puerto Rico half my life, and so I know how these work.  These are typically used to accommodate more students.  These are common in grades like Kindergarten where some students go to school from 7AM TO 12PM and then other students attend from 12:30PM TO 4PM.

i would say "están" :

hola, mi nombre es yo tengo hermanos y hermanas. mis padres celebretamos navidad juntos.

fill in the balnks and add a couple of remarks and you should have it!