These changes in the body ’ s circadian rhythm are in line with a time when we ’ re busier than ever. For most teens, the pressure to do well in school is more intense than when they were kids, and it ’ s harder to get by without studying hard. And teens also have other time demands---everything from sports and other extracurricular activities (课外活动) to fitting in a part-time job to save money for college. 3 .What ’ s the meaning of the underline phrase “ in line with ” in Paragraph 4?