Teacher burnout （倦怠）and student stress may be linked, according to a University of British Columbia study. The study is the first of its kind to examine the connection between teacher burnout and students' cortisol levels（可体松水平）, which are a biological indicator of stress.Researchers collected saliva（唾液） samples from over 400 elementary school children and tested their cortisol levels. They found that in classrooms in which teachers experienced more burnout, or feelings of emotional exhaustion, students' cortisol levels were elevated. Higher cortisol levels in elementary school children have been linked to learning difficulties as well as mental health problems."This suggests that stress contagion might be taking place in the classroom among students and their teachers, " said Eva Oberle, the study's lead author and newly appointed assistant professor with the Human Early Learning Partnership （HELP） at UBC's school of population and public health. "It is unknown what came first—elevated cortisol or teacher burnout. We consider the connection between student and teacher stress a cyclical problem in the classroom."Oberle said a stressful classroom climate could be a result of inadequate support for teachers, which may impact teachers' ability to effectively manage their students. A poorly managed classroom can contribute to students' needs not being met and increasing stress. This could be reflected in elevated cortisol levels in students.Alternatively, stress could originate from students, who may be more challenging to teach because of increases in anxiety, behavioural problems, or special needs. In this scenario, teachers could feel overwhelmed and report higher levels of burnout."Our study is a reminder of the systemic issues facing teachers and educators as classroom sizes increase and supports for teachers are cut, " said Oberle."It is clear from a number of recent research studies that teaching is one of the most stressful professions, and that teachers need adequate resources and support in their jobs in order to battle burnout and alleviate stress in the classroom, " said UBC education professor Kimberly Schonert-Reichl, the study's co-author and director of HELP. "If we do not support teachers, we risk the collateral damage of students."Which is the best title for the passage? A.How to Relieve Stress in the classB.A Puzzling Question of Egg and ChildrenC.The most Stressful Profession in the worldD.The Link Between Students Stress and Teacher BurnoutParagraph 4 and paragraph 5 are intended to make it clear that .A.teacher burnout may be the cause of the elevated cortisol levels in studentB.the connection students and teacher stress is a cyclical problemC.students with higher stress level are more likely to have learning difficultiesD.students' behavioural problems may result in teacher's higher level of burnoutAccording to the writer, many British teacher face the problem that .A.teachers are not well trained to deal with students' problemB.teachers' income increases but teaching resources are cutC.there are more students in each class and less support for teachersD.there is a widening gap between students' need and teachers' abilityWhich of the following statement is NOT true? A.The more burnout teachers experience, the higher cortisol levels in students.B.Adequate support may help teachers manage students effectively.C.Students will benefit as a result of reduced teacher burnout.D.High cortisol levels indicates high level of burnout.