single out 　(1)select from a group
　　　　　　　　(2) treat differently on the basis of sex or race

(1)She was singled out for her outstanding performance
(2)Rose was singled out by the teacher because her art project was so creative.

(3)The black students were singled out by the racist manager and given difficult assignments.
(4)I don't know why they singled it out, but my report was severely criticized at the meeting.