1.   But she found that the people who had treated her so kindly could turn very nasty indeed when they figured out what she was up to.

2.   The movie turns nasty when the evil stepfather barges into their idyll.

3.   Analysts warned the campaign could turn nasty if the mudslinging continued, despite united appeals for calm by newspapers.

4.   Analysts warned the election campaign could turn nasty if the mudslinging continued, despite united appeals for calm by newspapers.