Question

change to the negative form.
a) you are walking now
b) she is listenimg to music.
c) He is reading the newspaper now.
d) They are celebrating Halloween.

Answer 1

You are not walking now.
She is not listening to music.
He is not reading the newspaper now.
They are not celebrating halloween.

Answer 2

You are not walking now
she is not listening to music
he is not reading the newspaper now
the are not celebrating halloween 
No caso de "is not, are not... pode abreviar por exemplo; isn't, aren't...