阅读下面短文,在空白处填入1个适当的单词或括号内单词的正确形式。
At its most basic, stress 15 (see) as any change or pressure in the environment. Most people think of stress 16 a bad thing, but in reality most people need some of it. “A little stress can be 17 (help) to high schoolers in so many ways. It makes them want to study much 18 (hard). It helps push them,” says Mary Alvord, a psychologist(心理学家) in Maryland. Adolescence(青春期) is an important time 19 (learn) to cope with stress because teens can then cope with it better in college.
But too much stress will influence both the body 20 mind, Alvord says. In the short term it can cause anxiety(焦虑); over long periods of time, too much stress can cause heart problems. That’s bad for anyone, but it can be 21 (especial) bad for high schoolers: “Colleges are complaining(抱怨) that more and more kids are not paying much attention to 22 (they) studies, and they are dropping out and taking a long time to graduate. It’s not developmentally good for them to work so hard,” says Alvord. And since everyone has a different psychological capacity(能力) for stress, 23 is hard to know when a student is pushed to the point of 24 (influence) his or her health.