Dans la salle de Classe Crossword

A teacher writes on it everyday
It can be very heavy
You use it in maths
You put your pens in it
You gaze out at the world through it
If you make a mistake, you need it!
Not every student in the class gets to use one, yet!
You use it to keep your work in line
You put it up at the end of the day
You're not allowed this in class!
You use this to draw, not write
There's at least one in every classroom
You need it for your homework
You look at it hoping it'll go faster
It can be open, it can be closed
If you lose it, you may cry
Work will appear brighter if you use it
You learn how to use them in geography
Every subject has at least one
They come in different colours, usually black, blue or red