Сделать предложения вопросительными и отрицательными ? my cousin is twelve. management is difficult. we are future agricultural engineers. his mother-in-law is afraid of rats. medicine books are boring

1 Management is difficult. 
Is management is difficult?
Management isn't difficult. 
2 We are future agricultural engineers.
Are we future agricultural engineers?
We aren't future agricultural engineers.
3 His mother-in-law is afraid of rats.
Is his mother-in-law afraid of rats?
His mother-in-law isn't afraid of rats.
4 Medicine books are boring.
Are medicine books boring?
Medicine books aren't boring