tolong yang jago bahasa inggris

a)
(+) anton does his exercise.
(-) anton does not do his exercise.
(?) does anton do his exercise?

b)
(+) anton did his exercise.
(-) anton did not do his exercise.
(?) did anton do his exercise?

c)
(+) anton has done his exercise.
(-) anton has not done his exercise.
(?) has anton done his exercise?