Answers:

   `1.`

$(-)$ Mai doesn't often listening to music`.`

`(?)` Does Mai often listening to music`?`

   `2.`

$(-)$ Peter doesn't have `2` cats`.`

`(?)` Does Peter have `2` cats`?`

   `3.` 

$(-)$ These students aren't doing their homework now`.`

`(?)` Are these students doing their homework now`?`

1)Mai often listen to music

(-) Mai doesn't often listen to music

(?) Does Mai often listen to music ?

2)Peter has to cats

(-)Peter doesn't hasve to cats

(?) Does Peter have to cats ?

3)These students are doing the homework now

(-)These students aren't doing the homework now

(?) Are these students  doing the homework now?

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